update_test_checks.py: pick up --tool from UTC_ARGS

[nhaehnle]

Summary

It's not clear to me how to write a test for this. The tests run in an
environment where the tools may not be in PATH, and so the existing
custom-tool.test needs to use --tool-binary when invoking
update_test_checks.py. But it can't do so without also using --tool.

This change does fix a problem though with using
update_any_test_checks.py in an environment where the tools *are*
available in PATH.

[nikic]

LGTM

llvm/utils/update_test_checks.py

def main():
 
   script_name = os.path.basename(__file__)
 
   if initial_args.tool_binary:
     tool_basename = os.path.basename(initial_args.tool_binary)
     if not re.match(r'^%s(-\d+)?(\.exe)?$' % (initial_args.tool), tool_basename):
       common.error('Unexpected tool name: ' + tool_basename)
       sys.exit(1)
-  tool_basename = initial_args.tool
 
   for ti in common.itertests(initial_args.tests, parser,
                              script_name='utils/' + script_name):
     # If requested we scrub trailing attribute annotations, e.g., '#0', together with whitespaces
     if ti.args.scrub_attributes:
       common.SCRUB_TRAILING_WHITESPACE_TEST_RE = common.SCRUB_TRAILING_WHITESPACE_AND_ATTRIBUTES_RE
     else:
       common.SCRUB_TRAILING_WHITESPACE_TEST_RE = common.SCRUB_TRAILING_WHITESPACE_RE
 
+    tool_basename = ti.args.tool
+
     prefix_list = []
     for l in ti.run_lines:
       if '|' not in l:
         common.warn('Skipping unparsable RUN line: ' + l)
         continue
 
       commands = [cmd.strip() for cmd in l.split('|')]
       assert len(commands) >= 2