Ignore public API checks if COMMIT=false is in the description

BUG=skia:

Review URL: https://codereview.chromium.org/1006473002
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index d62249a..b539704 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -143,6 +143,8 @@
   """
   results = []
   results.extend(_CommonChecks(input_api, output_api))
+  # TODO(rmistry): Remove the below it is only for testing!!!
+  results.extend(_CheckLGTMsForPublicAPI(input_api, output_api))
   return results
 
 
@@ -254,6 +256,11 @@
       # It is a revert CL, ignore the public api owners check.
       return results
 
+    if re.search(r'^COMMIT=false$', issue_properties['description'], re.M):
+      # Ignore public api owners check for COMMIT=false CLs since they are not
+      # going to be committed.
+      return results
+
     match = re.search(r'^TBR=(.*)$', issue_properties['description'], re.M)
     if match:
       tbr_entries = match.group(1).strip().split(',')