Add option --build-only to the test runner

tools/test.py

 #!/usr/bin/env python
 #
 # Copyright 2008 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 1066 matching lines @@
       default='release')
   result.add_option("-v", "--verbose", help="Verbose output",
       default=False, action="store_true")
   result.add_option("-S", dest="scons_flags", help="Flag to pass through to scons",
       default=[], action="append")
   result.add_option("-p", "--progress",
       help="The style of progress indicator (verbose, dots, color, mono)",
       choices=PROGRESS_INDICATORS.keys(), default="mono")
   result.add_option("--no-build", help="Don't build requirements",
       default=False, action="store_true")
+  result.add_option("--build-only", help="Only build requirements, don't run the tests",
+      default=False, action="store_true")
   result.add_option("--report", help="Print a summary of the tests to be run",
       default=False, action="store_true")
   result.add_option("-s", "--suite", help="A test suite",
       default=[], action="append")
   result.add_option("-t", "--timeout", help="Timeout in seconds",
       default=60, type="int")
   result.add_option("--arch", help='The architecture to run tests for',
       default='none')
   result.add_option("--simulator", help="Run tests with architecture simulator",
       default='none')
@@ skipping 157 matching lines @@
     reqs = [ ]
     for path in paths:
       reqs += root.GetBuildRequirements(path, context)
     reqs = list(set(reqs))
     if len(reqs) > 0:
       if options.j != 1:
         options.scons_flags += ['-j', str(options.j)]
       if not BuildRequirements(context, reqs, options.mode, options.scons_flags):
         return 1
 
+  # Just return if we are only building the targets for running the tests.
+  if options.build_only:
+    return 0
+  
   # Get status for tests
   sections = [ ]
   defs = { }
   root.GetTestStatus(context, sections, defs)
   config = Configuration(sections, defs)
 
   # List the tests
   all_cases = [ ]
   all_unused = [ ]
   unclassified_tests = [ ]
@@ skipping 66 matching lines @@
     for entry in timed_tests[:20]:
       t = FormatTime(entry.duration)
       sys.stderr.write("%4i (%s) %s\n" % (index, t, entry.GetLabel()))
       index += 1
 
   return result
 
 
 if __name__ == '__main__':
   sys.exit(Main())