Fix part of PR 110293: `A NEEQ (A NEEQ CST)` part

Fix part of PR 110293: `A NEEQ (A NEEQ CST)` part

This fixes part of PR 110293, for the outer comparison case
being `!=` or `==`.  In turn PR 110539 is able to be optimized
again as the if statement for `(a&1) == ((a & 1) != 0)` gets optimized
to `false` early enough to allow FRE/DOM to do a CSE for memory store/load.

OK? Bootstrapped and tested on x86_64-linux with no regressions.

gcc/ChangeLog:

	PR tree-optimization/110293
	PR tree-optimization/110539
	* match.pd: Expand the `x != (typeof x)(x == 0)`
	pattern to handle where the inner and outer comparsions
	are either `!=` or `==` and handle other constants
	than 0.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/pr110293-1.c: New test.
	* gcc.dg/tree-ssa/pr110539-1.c: New test.
	* gcc.dg/tree-ssa/pr110539-2.c: New test.
	* gcc.dg/tree-ssa/pr110539-3.c: New test.
	* gcc.dg/tree-ssa/pr110539-4.c: New test.