These have been effectively disabled ever since 'nvptx' was added to
the REQUIRES clauses, because REQUIRES does not support triple checks.
The new 'target=<triple>' is supported, so switch to that scheme.
Fix up XFAIL annotations, now that these tests are actually run.
Part of the project to eliminate special handling for triples in lit
expressions.
So the idea here is to actually run the tests, but that they all are expected to fail at the moment?