Port verify-binding-redirects.ps1 to rel/18.5

[nohwnd]

Ports the binding redirect verification script (and its wiring from �erify-nupkgs.ps1) from main/rel/18.7 to rel/18.5, so we can validate on this branch that the newVersion in each binding redirect actually matches the shipped assembly.

The script runs against the extracted Microsoft.TestPlatform.*.nupkg layout produced by verify-nupkgs.ps1. For each of vstest.console.exe, testhost.x86.exe, and datacollector.exe it:

• finds the exe in the packaged layout
• follows <probing privatePath> from the app.config
• for every <dependentAssembly> reads the shipped DLL version
• compares it to the redirect's newVersion

In CI it fails with the list of mismatches plus fix instructions. Locally it auto-updates the source app.config files (preserving whitespace and BOM) so you can just commit the result.

Ran cleanly on rel/18.5 HEAD (v18.5.0) against a Debug build — everything green, including System.Collections.Immutable 9.0.0.0 which was the one we wanted to verify.

[nohwnd]

Flaky on ccparallel.