Fix GC tests.

[sandreenko]

Jit can extend lifetime of temp objects after call to GC.Collect(), so we should not have any temp in the same scope with final GC.Collect();.

incorrect example 1:

var a = new Object(); // Jit can create a temp that will be alive after GC.Collect().
a = null;
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();

incorrect example 2:

SetLink();
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();

void SetLink() // this method could be inlined, we will get the first example.
{
       var a = new Object();
       a = null;
}

Incorrect example 3:

var a = SetLink(); // Jit can create a temp here with a long lifetime.
a = null;
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();

[MethodImpl(MethodImplOptions.NoInlining)]
Object SetLink()
{
       return new Object();
}

correct example 1:

SetLink();
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();

[MethodImpl(MethodImplOptions.NoInlining)]
void SetLink() // All temps are in this method and it is protected with NoInlining attribute.
{
       var a = new Object();
       a = null;
}

Fixes #17588.

The same problem as #15156.

[sandreenko]

@dotnet-bot test Windows_NT arm Cross Checked r2r_jitstressregs3 Build and Test
@dotnet-bot test Windows_NT arm Cross Checked jitstress2_jitstressregs3 Build and Test

[sandreenko]

cc @Maoni0

[Maoni0]

thanks!