[presubmit] Allow use of test functions in runtime-test.cc

We consider some function "test-only" function, e.g. if they have a
"ForTesting" in their name. The src/runtime/runtime-test.cc file should
be allowed to call such functions.

R=tmrts@chromium.org
CC=ahaas@chromium.org

Change-Id: Ib57bba36ba35f29c7673d4cef6d6b1e5ad9c7f65
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2339623Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69308}

PRESUBMIT.py

@@ -62,6 +62,8 @@ _TEST_CODE_EXCLUDED_PATHS = (
     r'src[\\\/]compiler[\\\/]ast-graph-builder\.cc',
     # Test extension.
     r'src[\\\/]extensions[\\\/]gc-extension\.cc',
+    # Runtime functions used for testing.
+    r'src[\\\/]runtime[\\\/]runtime-test\.cc',
 )