[clang] [clang] Handle invalid template template arguments in partial ordering (PR #233138)

[Oliver Hunt via cfe-commits]

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ojhunt wrote:

This is literally just removing the assertion. The assertion is present because we are not handling this scenario.

The fact that we have an example in which this can be hit does not indicate that it is (1) correct for us to reach this point, or (2) that the current non-assertion-build behavior is correct.

https://github.com/llvm/llvm-project/pull/233138