middle-end/115110 - Fix view_converted_memref_p

middle-end/115110 - Fix view_converted_memref_p

view_converted_memref_p was checking the reference type against the
pointer type of the offset operand rather than its pointed-to type
which leads to all refs being subject to view-convert treatment
in get_alias_set causing numerous testsuite fails but with its
new uses from r15-512-g9b7cad5884f21c is also a wrong-code issue.

	PR middle-end/115110
	* tree-ssa-alias.cc (view_converted_memref_p): Fix.

(cherry picked from commit a5b3721c06646bf5b9b50a22964e8e2bd4d03f5f)