romcc: Rewrite the test system

Differences:
 - The test logic is now only implemented in one place (pending the
   deletion of the old parts), whereas it previously was implemented
   both as make rules and as a pair of shell scripts.
 - Tests don't need to be registered anymore. Just adding a new file
   with the correct name is enough to have it tested.
 - The code is hopefully more readable and maintainable.
 - The new test script supports colors (if the standard output is a
   terminal and --nocolor was not passed on the command line).

Things to do in follow-up patches:
 - Remove the old test code
 - Test or remove fail_test*.c, hello_world*.c and raminit_test*.c
 - Fix regressions that have built up over the years, while making sure
   not to introduce new ones
 - Makefile integration
 - Jenkins integration

There are tests in the makefile that specify -fno-always-inline, but
this option doesn't exist anymore, so I didn't port them over.

Change-Id: Idd6b89368c1e36555cb880c37bbe07035c938cd7
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-on: https://review.coreboot.org/14291
Reviewed-by: Martin Roth <martinroth@google.com>
Tested-by: build bot (Jenkins)
2 files changed