Misc LSRA throughput improvements (#85842)

Misc LSRA throughput improvements (#85842)

* Use BitOperations in few hot methods

* Do not pass RegisterType for non-arm sarchitectures

* Add clearAssignedInterval()

* Consume clearAssignedInterval()

* Do not pass RegisterType for updateInterval()

* Revert the change in genFindLowestBit()

* Revert "Use BitOperations in few hot methods"

This reverts commit a75a7da436fe616d8226d8f2a4c5d50c0f447827.

* Add the missing case for clearAssignedInterval()

* Remove logging

* jit formatting

* Use popcount intrinsics

* Revert "Use popcount intrinsics"

This reverts commit 0b3da210a8b754521de29d40e01072fb1b01adc7.

* revert unintentional change from superpmi.py

* Revert "Do not pass RegisterType for non-arm sarchitectures"

This reverts commit 46d4d3d88704beca5f0817db3a6e48fc1a14dac6.

* fix the merge conflicts