Replace COMPlus with DOTNET prefix

[am11]

The configuration system in coreclr and mono started supporting DOTNET_ prefix in net6.0. Using DOTNET_ is preferred because it has precedence over COMPlus_.

This matches the behavior by prioritizing DOTNET_ prefix and moving COMPlus_ to fallback in product code. Tests are using the new prefix.

Release Notes Entry

Use the DOTNET prefix when detecting environment variables and prefer it over the COMPlus prefix.

[jander-msft]

Thanks for updating the prefix usage!

[jander-msft]

/backport to release/8.0

[github-actions]

Started backporting to release/8.0: https://github.com/dotnet/dotnet-monitor/actions/runs/11262092143

[github-actions]

@jander-msft backporting to release/8.0 failed, the patch most likely resulted in conflicts.

Please backport manually using one of the below commands, followed by git am --continue once the merge conflict has been resolved.

PowerShell

(Invoke-WebRequest "https://github.com/dotnet/dotnet-monitor/commit/78bc9add206f83464f8542fb4c64b77accd59b42.patch").Content | git am --3way --ignore-whitespace --exclude="documentation/**.md" --keep-non-patch

Bash

curl -sSL "https://github.com/dotnet/dotnet-monitor/commit/78bc9add206f83464f8542fb4c64b77accd59b42.patch" | git am --3way --ignore-whitespace --exclude="documentation/**.md" --keep-non-patch

---

git am error output:

$ git am --3way --ignore-whitespace --exclude="documentation/**.md" --keep-non-patch changes.patch

Applying: Replace COMPlus with DOTNET prefix (#7434)
Using index info to reconstruct a base tree...
M	src/Tools/dotnet-monitor/ParameterCapturing/CaptureParametersOperation.cs
M	src/Tools/dotnet-monitor/RuntimeInfo.cs
Falling back to patching base and 3-way merge...
Auto-merging src/Tools/dotnet-monitor/RuntimeInfo.cs
CONFLICT (content): Merge conflict in src/Tools/dotnet-monitor/RuntimeInfo.cs
Auto-merging src/Tools/dotnet-monitor/ParameterCapturing/CaptureParametersOperation.cs
CONFLICT (content): Merge conflict in src/Tools/dotnet-monitor/ParameterCapturing/CaptureParametersOperation.cs
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0001 Replace COMPlus with DOTNET prefix (#7434)
Error: The process '/usr/bin/git' failed with exit code 128