Fixup phys_dev_inst_ext_tests

Add tests which exercise the case of a ICD being 1.0 with support for
VK_KHR_get_physical_device_properties2 while the ICD enables 1.1 and the
extension but tries to use the extension.

Removed TEST_F in this file, wasn't needed and caused an extra ICD to be found.

Converted the CompareXXX functions from internally using ASSERT_EQ to returning
a bool. This made the tests more robust since ASSERT_EQ in a function will just
return the function early, not end the test.