[NFC] Remove max_align.c LIT testcase

Since we fixed the definition of `SuitableAlign`[https://reviews.llvm.org/D88659],
`max_align_t` and `__BIGGEST_ALIGNMENT__` are not necessarily the same always.

The original testcase was added here: https://reviews.llvm.org/D59048

Differential Revision: https://reviews.llvm.org/D90187