[WIP] Fix dotnet --debug switch functionality on Unix

[Copilot]

Thanks for assigning this issue to me. I'm starting to work on it and will keep this PR's description up to date as I form a plan and make progress.

Original prompt

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This section details on the original issue you should resolve

<issue_title>dotnet --debug switch no longer works (unix)</issue_title>
<issue_description>When we now try to run our --debug flag as defined by src/Cli/Microsoft.DotNet.Cli.Utils/DebugHelper.cs, the flag doesn't work and we get a failure with:

./artifacts/bin/redist/Debug/dotnet/dotnet --debug --info

Could not execute because the specified command or file was not found.
Possible reasons for this include:
  * You misspelled a built-in dotnet command.
  * You intended to execute a .NET program, but dotnet---debug does not exist.
  * You intended to run a global tool, but a dotnet-prefixed executable with this name could not be found on the PATH.

However, it seems that skipping the native host resolution re-enables the flag to work:
./artifacts/bin/redist/Debug/dotnet/dotnet exec ./artifacts/bin/redist/Debug/dotnet/sdk/10.0.103-dev/dotnet.dll --debug --info

My understanding is that there was some change to the host that caused this. I thought it was the tool lookup logic or the - conversion lookup, but I'm not sure.

Maybe I'm also doing something wrong but it seems busted to me. Seems like it may be a linux issue, so it may also have never worked on unix.</issue_description>

Comments on the Issue (you are @copilot in this section)

@nagilson Btw, at first I thought maybe it's because I used release instead of debug, but I also tried removing the debug conditional switch. @marcpopMSFT Triage: @nagilson what branch are you seeing this on? Others can't reproduce in 10 branches. @nagilson It was release/10.0.1xx on Linux (gh codespaces)

• Fixes dotnet --debug switch no longer works (unix) #52471

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