[minor] mark scripts as executable

if a filename ends with `.py` and  the file begins with '#!.*python.*',
make it executable.

Change-Id: I41de516ff37343d3b0979bde9fd61813aec7365c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254439
Commit-Queue: Hal Canary <halcanary@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Auto-Submit: Hal Canary <halcanary@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>

tools/calmbench/calmbench.py

@@ -1,4 +1,4 @@
-#!/usr/bin/pyton
+#!/usr/bin/python
 
 # Copyright 2017 Google Inc.
 #