[LegacyPM] Remove ThreadSanitizerLegacyPass

Using the legacy PM for the optimization pipeline was deprecated in 13.0.0.
Following recent changes to remove non-core features of the legacy
PM/optimization pipeline, remove ThreadSanitizerLegacyPass.

Reviewed By: #sanitizers, vitalybuka

Differential Revision: https://reviews.llvm.org/D124209