Add match patterns for `a ? onezero : onezero` where one of the two operands are constant

This adds a match pattern that are for boolean values
that optimizes `a ? onezero : 0` to `a & onezero` and
`a ? 1 : onezero` to `a | onezero`.

This was reported a few times and I thought I would finally
add the match pattern for this.

This hits a few times in GCC itself too.

Notes on the testcases:
* phi-opt-2.c: This now is optimized to `a & b` in phiopt rather than ifcombine
* phi-opt-25b.c: The test part that was failing was parity which now gets `x & y` treatment.
* ssa-thread-21.c: there is no longer a threading opportunity, so need to disable phiopt.
  Note PR 109957 is filed for the now missing optimization in that testcase too.

gcc/ChangeLog:

	PR tree-optimization/89263
	PR tree-optimization/99069
	PR tree-optimization/20083
	PR tree-optimization/94898
	* match.pd: Add patterns to optimize `a ? onezero : onezero` with
	one of the operands are constant.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/phi-opt-2.c: Adjust the testcase.
	* gcc.dg/tree-ssa/phi-opt-25b.c: Adjust the testcase.
	* gcc.dg/tree-ssa/ssa-thread-21.c: Disable phiopt.
	* gcc.dg/tree-ssa/phi-opt-27.c: New test.
	* gcc.dg/tree-ssa/phi-opt-28.c: New test.
	* gcc.dg/tree-ssa/phi-opt-29.c: New test.
	* gcc.dg/tree-ssa/phi-opt-30.c: New test.
	* gcc.dg/tree-ssa/phi-opt-31.c: New test.
	* gcc.dg/tree-ssa/phi-opt-32.c: New test.