Test cases for bugs in Mesa value range analysis optimizations
Only the tests added by the first commit reproduced the actual bug from https://bugs.freedesktop.org/show_bug.cgi?id=111308. The others were discovered along the way. All of the cases pass on Mesa before 96fcb3f95bd, and almost all of them fail after.
fs-eq-nan-tautology.shader_test is the only test that also passes after.