Fix VersionBubbles test (dotnet/coreclr#25392)

Fix VersionBubbles test (dotnet/coreclr#25392)

The test was not crossgening with large version bubble enabled since
the part of the .csproj that generates part of the .sh/.bat test
running scripts was commented out. There were also bugs in the
commented out code. Also, to ensure that it works, tiered compilation
and jit minopts need to be disables to ensure that the test method
won't be re-jitted.

Commit migrated from https://github.com/dotnet/coreclr/commit/65d75c7e2d3b8a35249ad66413f98d8c6075e699