The previous patches added the necessary support for global constructors
used to register tests. This patch enables the NVPTX target to build
and run the unit tests on the GPU. Currently this only tests the ctype
tests, but adding more should be straightforward from here on.
This ran all the ctest unit tests when run on an sm_70.
Depends on D149517 D149527
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D149532
A convenience wrapper name `add_libc_test` is also added which adds both
a unit test and a hermetic test. The ctype tests have been switched over
to use add_libc_test.
Reviewed By: jhuber6
Differential Revision: https://reviews.llvm.org/D148756
