Call dealias after stripping type variables for tupleElementTypesUpTo

[aherlihy]

Fixes #22643 and the first test case of #22645.

[EugeneFlesselle]

I appears you also fixed #22645 (including the ExhibitE) 👍, I think we can close it as solved with this PR too

[aherlihy]

ExhibitE is weird for me, running this test case crashes the compiler (also on main) only when run from the pickling tests in testCompilation, so normal use bin/scalac tests/pos/i22645b.scala does not cause a compiler crash.
From testCompilation, it crashes with:

[info] Test dotty.tools.dotc.CompilationTests.pickling started
[                                        ] completed (0/1, 0 failed, 1s)
Fatal compiler crash when compiling: tests/pos/i22645b.scala:
pickling difference for object ExhibitE in tests/pos/i22645b.scala 

That looks like an unrelated pickling issue that may need a separate ticket.

[EugeneFlesselle]

That looks like an unrelated pickling issue with the test suite that may need a separate ticket.

Oh, that tends to happen with match types, you can add the test case to the pos-test-pickling.excludelist.

[aherlihy]

Oh great, thanks! Added the test case back now, I'll close both issues when this is PR is done