System.Uri does not compress paths when an authority is not present

### Description

During playing around with property based testing of the .NET URI parsing implementation I noticed the following violations of expected properties:

### Reproduction Steps

- URI normalization / canonicalization is not idempotent.
(normalizing twice is not the same as normalizing once).

```fsharp
let uri = "https://microsoft.com/%20"
let normalized1 = System.Uri(uri, System.UriKind.Absolute).ToString()
let normalized2 = System.Uri(normalized1, System.UriKind.Absolute).ToString()
printfn "%A" normalized1 // "https://microsoft.com/ "
printfn "%A" normalized2 // "https://microsoft.com/"
printfn "%A" (normalized1 = normalized2) // false
```

- URI normalization / canonicalization is not idempotent.
(normalizing twice is not the same as normalizing once).

```fsharp
let uri = "aaaa:b%7c/"
let normalized1 = System.Uri(uri, System.UriKind.Absolute).ToString()
let normalized2 = System.Uri(normalized1, System.UriKind.Absolute).ToString()
printfn "%A" normalized1 // "aaaa:b|/"
printfn "%A" normalized2 // "aaaa:b:/"
printfn "%A" (normalized1 = normalized2) // false
```

- URI normalization / canonicalization results in path with unresolved/not removed dot segments.
Compare https://datatracker.ietf.org/doc/html/rfc3986#section-5.2.4 Remove Dot Segments
(May be somewhat related to #31300)

```fsharp
let uri = "xmgz:/.///b?y"
let normalized = System.Uri(System.Uri( uri, System.UriKind.Absolute).ToString(), System.UriKind.Absolute)
printfn "uri: %A" (normalized.ToString()) // "xmgz:/.///b?y"
printfn "path: %A" normalized.AbsolutePath // "/.///b"
printfn "path segments: %A" normalized.Segments // [|"/"; "./"; "/"; "/"; "b"|]
```

It could be that some of these examples are false positives and that I misunderstood the desired behavior.
Even if they are true positives, I don't think they are security-relevant.

The examples are fully self-contained; each given example can be run with `dotnet fsi ` (where `` simply contains exactly the code from the respective snippet).

For background information on generating examples compare also https://github.com/stfnw/talk-introduction-to-property-based-testing/blob/4afa26d76f9df193e2ec57c9bee5a9c02a060b82/code/uri-parsing.fsx.

### Expected behavior

The stated properties should intuitively hold.

### Actual behavior

The properties don't hold.

### Regression?

N/A

### Known Workarounds

N/A

### Configuration

```shell
# dotnet fsi --version
Microsoft (R) F# Interactive version 14.0.102.0 for F# 10.0

# uname -a
Linux 16e9db91a078 6.12.63+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.63-1 (2025-12-30) x86_64 GNU/Linux

# # installed from Microsoft repos https://packages.microsoft.com/debian/13/prod trixie/main amd64 Packages

# dpkg -l dotnet-*-10.0
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==========================-============-============-============================================
ii dotnet-apphost-pack-10.0 10.0.2 amd64 Microsoft.NETCore.App.Host 10.0.2
ii dotnet-hostfxr-10.0 10.0.2 amd64 Microsoft .NET Host FX Resolver - 10.0.2
ii dotnet-runtime-10.0 10.0.2 amd64 Microsoft.NETCore.App.Runtime.CoreCLR 10.0.2
ii dotnet-runtime-deps-10.0 10.0.2 amd64 dotnet-runtime-deps-debian 10.0.2
ii dotnet-sdk-10.0 10.0.102 amd64 Microsoft .NET SDK 10.0.102
ii dotnet-targeting-pack-10.0 10.0.2 amd64 Microsoft.NETCore.App.Ref 10.0.2

# dpkg -s dotnet-sdk-10.0
Package: dotnet-sdk-10.0
Status: install ok installed
Priority: standard
Section: libs
Installed-Size: 411370
Maintainer: .NET Team
Architecture: amd64
Version: 10.0.102
Depends: dotnet-runtime-10.0 (>= 10.0.2), dotnet-targeting-pack-10.0 (>= 10.0.2), dotnet-apphost-pack-10.0 (>= 10.0.2), aspnetcore-runtime-10.0 (>= 10.0.2), aspnetcore-targeting-pack-10.0 (>= 10.0.2)
Description: Microsoft .NET SDK 10.0.102
.NET is a development platform that you can use to build command-line applications, microservices and modern websites. It is open source, cross-platform and is supported by Microsoft. We hope you enjoy using it! If you do, please consider joining the active community of developers that are contributing to the project on GitHub (https://github.com/dotnet/core). We happily accept issues and PRs.
Homepage: https://github.com/dotnet/core

# dpkg -s dotnet-runtime-10.0
Package: dotnet-runtime-10.0
Status: install ok installed
Priority: standard
Section: libs
Installed-Size: 80278
Maintainer: .NET Team
Architecture: amd64
Version: 10.0.2
Depends: dotnet-hostfxr-10.0 (>= 10.0.2), dotnet-runtime-deps-10.0 (>= 10.0.2)
Description: Microsoft.NETCore.App.Runtime.CoreCLR 10.0.2
.NET is a development platform that you can use to build command-line applications, microservices and modern websites. It is open source, cross-platform and is supported by Microsoft. We hope you enjoy using it! If you do, please consider joining the active community of developers that are contributing to the project on GitHub (https://github.com/dotnet/core). We happily accept issues and PRs.
Homepage: https://github.com/dotnet/core
```

### Other information

_No response_

Empieza ejecutando los tres fragmentos autocontenidos de F# con dotnet fsi y compara sus resultados con RFC 3986 sección 5.2.4. El punto de entrada es System.Uri; se considera terminado cuando se haya determinado qué propiedades de normalización informadas son el comportamiento previsto y se haya identificado la cobertura de regresión adecuada, ya que no se menciona ningún archivo del repositorio ni ninguna prueba.

Escrito por el modelo de indexación a partir del texto del issue.