Add info message with current spec filename to test generators

If test specification in python contained a mistake, exec would fail and
it wouldn't show a filename of the file that was being processed. This
was confusing when generating several tests because the last filename
listed before an error was actually the file that was successfully
generated.

Test: Regenerated the tests
Change-Id: Ia1bdf6802e8855b0fa9666a6e3a37d36205acbda
Merged-In: Ia1bdf6802e8855b0fa9666a6e3a37d36205acbda
(cherry picked from commit 4bb11a32)