update bootstrap to not perform cross compilation when building tests

Author: bkhouri

Utilities/bootstrap

@@ -400,6 +400,8 @@ def test(args):
     build(args)
 
     logging.info("Testing")
+    # When building the tests, only build for the host platform.
+    args.cross_compile_hosts = False
     parse_test_args(args)
     cmd = [
         os.path.join(args.bin_dir, "swift-test")