Strip undef implying attributes when moving calls

When hoisting/moving calls to locations, we strip unknown metadata. Such calls are usually marked `speculatable`, i.e. they are guaranteed to not cause undefined behaviour when run anywhere. So, we should strip attributes that can cause immediate undefined behaviour if those attributes are not valid in the context where the call is moved to.

This patch introduces such an API and uses it in relevant passes. See
updated tests.

Fix for PR50744.

Reviewed By: nikic, jdoerfert, lebedev.ri

Differential Revision: https://reviews.llvm.org/D104641