This patch introduces a new spv_ptrcast intrinsic for tracking expected
pointer types. The change fixes multiple OpenCL CTS regressions due the
switch to opaque pointers (e.g. basic/hiloeo).
These tests are currently failing and their fix is being tracked in
Issue #60133. Marking them as XFAIL for now will get the test suite to a
passing state so we can work on adding a GitHub action to automatically
run these tests on a PR bot to help keep the tree green.
Also removed the no-longer supported -opaque-pointers=0 flag from the
couple tests where it was remaining.
