[MachineSink] Add a loop sink limit

To make sure compile-times don't regress, add an option to restrict the number
of instructions considered for sinking as alias analysis can be expensive and
for the same reason also skip large blocks.

Differential Revision: https://reviews.llvm.org/D96485

GitOrigin-RevId: 7f3170ec1943a25a09beb0a989ebc83c9c238f97
2 files changed