Remove Arcade HelixResultsDestinationDir workaround

[BruceForstall]

Due to a bug in the implementation of HelixResultsDestinationDir, many superpmi and related .proj files in the src\coreclr\scripts directory contain explicit code to set this variable, namely:

    <!-- Workaround until https://github.com/dotnet/arcade/pull/6179 is not available -->
    <HelixResultsDestinationDir>$(BUILD_SOURCESDIRECTORY)\artifacts\helixresults</HelixResultsDestinationDir>

After dotnet/arcade#10630 is available, this should no longer be necessary, as the default is set to exactly this value.

When dotnet/arcade#10630 propagates to dotnet/runtime, remove all these settings to simplify the project files.

category:eng-sys
theme:build
skill-level:beginner
cost:small
impact:small

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Issue Details

---

Due to a bug in the implementation of HelixResultsDestinationDir, many superpmi and related .proj files in the src\coreclr\scripts directory contain explicit code to set this variable, namely:

    <!-- Workaround until https://github.com/dotnet/arcade/pull/6179 is not available -->
    <HelixResultsDestinationDir>$(BUILD_SOURCESDIRECTORY)\artifacts\helixresults</HelixResultsDestinationDir>

After dotnet/arcade#10630 is not available, this should no longer be necessary, as the default is set to exactly this value.

When dotnet/arcade#10630 propagates to dotnet/runtime, remove all these settings to simplify the project files.

Author:	BruceForstall
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	8.0.0