Forbid creation of non-faulting null-check nodes. (#77078)

Forbid creation of non-faulting null-check nodes. (#77078)

* Forbid creation of non-faulting null-check nodes.

* Skip null check if op1 cannot be null.

* x86 bug fix for Skip gtChangeOperToNullCheck if it cannot be null.

* Fix Arm64 AVE: Do not lower indir when NOP.

* formatting fix.

* Arm64 regression bug fix that removes const bool for a variable.

* Preserve const and shorten expression.

* Fix format.

* Addressed code review feedback

* Forbid creation of non-faulting nullcheck node: Addressed feedback

* Forbid creation of non-faulting null-check nodes: Remove duplicate codes that was supposed to be deleted.