Url.RouteUrl is blank in ASP.NET Core 3.0

### Describe the bug
We are upgrading an ASP.NET Core 2.2. MVC app to 3.0 but Url.RouteUrl gives blank href's and inconsistency on link creation. What are we doing wrong?

### To Reproduce
Steps to reproduce the behavior:
1. Using this version of ASP.NET Core 3.0
2. Run this code:

**Example 1 -wrong result**
Returns https://example.org/us/blog/some-title-6 in 2.2 but is blank in 3.0:

```
string url = Url.RouteUrl("blog-details", new { title = item.Title, id = item.Id });

[Route("~/{lang}/blog/{title}-{id}", Name= "blog-details")]
public async Task Details(string title, int id)
{
}
```
We have tried these constructions but result is not satisfactory:
```
Link here
url = Url.Action("Details", "Blog", new { id = item.Id, title = item.Title });
url = Url.RouteUrl(new { action = "Details", controller = "Blog", id = item.Id, title = item.Title });
```
// Returns https://example.org/us/blog/details/6?title=some-title

**Startup.cs**

```
public void ConfigureServices(IServiceCollection services)
{
...
services.AddControllersWithViews(options =>
{
options.Filters.Add(new MiddlewareFilterAttribute(typeof(LocalizationPipeline)));
})
.AddViewLocalization(LanguageViewLocationExpanderFormat.SubFolder)
.AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix);
services.AddRazorPages();

services.AddRouting(options =>
{
options.ConstraintMap.Add("lang", typeof(LanguageRouteConstraint));
options.LowercaseUrls = true;
options.AppendTrailingSlash = false;
});
...
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
...
app.UseRouting();
app.UseAuthentication();
app.UseAuthorization();

app.UseResponseCompression();

app.UseEndpoints(endpoints =>
{
endpoints.MapControllers(); // attribute routing
endpoints.MapControllerRoute("areas", "{lang:lang}/{area:exists}/{controller=Home}/{action=Index}/{id?}");
endpoints.MapControllerRoute("LocalizedDefault", "{lang:lang}/{controller=Home}/{action=Index}/{id?}");
endpoints.MapControllerRoute("Naked", "/{controller=Home}/{action=Index}");
endpoints.MapHealthChecks("/health");
});
}

```
**Example 2 - wrong result**
Returns https://example.org/us/home/pricing instead of
https://example.org/us/pricing

```
Pricing

[Route("~/{lang}/pricing")]
public async Task Pricing()
{
...
}

```

**Example 3 - correct result**
Returns correct https://example.org/us/signup/customer

```
Sign up

[Route("~/{lang}/signup/customer")]
public IActionResult Customer()
{
...
}
```

### Additional context
`dotnet --info`

.NET Core SDK (reflecting any global.json):
Version: 3.0.100
Commit: 04339c3a26

Runtime Environment:
OS Name: Windows
OS Version: 10.0.18362
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\3.0.100\

Host (useful for support):
Version: 3.0.0
Commit: 7d57652f33

.NET Core SDKs installed:
2.1.202 [C:\Program Files\dotnet\sdk]
2.1.502 [C:\Program Files\dotnet\sdk]
2.1.504 [C:\Program Files\dotnet\sdk]
2.1.505 [C:\Program Files\dotnet\sdk]
2.1.507 [C:\Program Files\dotnet\sdk]
2.1.602 [C:\Program Files\dotnet\sdk]
2.1.604 [C:\Program Files\dotnet\sdk]
2.1.700 [C:\Program Files\dotnet\sdk]
2.1.801 [C:\Program Files\dotnet\sdk]
2.1.802 [C:\Program Files\dotnet\sdk]
2.2.100 [C:\Program Files\dotnet\sdk]
2.2.102 [C:\Program Files\dotnet\sdk]
2.2.104 [C:\Program Files\dotnet\sdk]
2.2.105 [C:\Program Files\dotnet\sdk]
2.2.203 [C:\Program Files\dotnet\sdk]
2.2.301 [C:\Program Files\dotnet\sdk]
3.0.100 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
Microsoft.AspNetCore.All 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Ref https://github.com/aspnet/AspNetCore/issues/12794