[prange] Use type agnostic range in phiopt [PR115191]

[prange] Use type agnostic range in phiopt [PR115191]

Fix a use of int_range_max in phiopt that should be a type agnostic
range, because it could be either a pointer or an int.

	PR tree-optimization/115191

gcc/ChangeLog:

	* tree-ssa-phiopt.cc (value_replacement): Use Value_Range instead
	of int_range_max.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/pr115191.c: New test.