[Debugger Perf] Conditional BP evaluation on Linux is SLOW

## Environment data
`dotnet --info` output:
VS Code version:
C# Extension version: 1.7.0

I ran the following code on Linux:
```CS
static void Main(string[] args)
{
var sw = new System.Diagnostics.Stopwatch();
sw.Start();
for (int i = 0; i < 100; i++)
{
var elapsed = sw.Elapsed;
// Do Something with i
int j = i; // bp here on i == 50
j++;
}
}
```

with a conditional breakpoint set on the specified line. The condition was `i == 50`.

When the breakpoint is finally hit, the value of `elapsed` is 5.7 seconds. This seems incredibly slow. On my Windows machine (granted it's a different machine), the value of `elapsed` is 0.35 seconds.