[X86] Increase the depth threshold required to form VPERMI2W/VPERMI2B in shuffle combining

These instructions are implemented with two port 5 uops and one port 015 uop so they are more complicated that most shuffles.

This patch increases the depth threshold for when we form them during shuffle combining to try to limit increasing the number of uops especially on port 5.

Differential Revision: https://reviews.llvm.org/D88503