scripts: Misc cleanup

- Review feedback from Vulkan-Tools review
- Make vk_validation_stats.py quiet by default instead of blanket
  discard of all generator stdout

Change-Id: Iae3a0e2b7dac6e67ff05f61a4595b636ea643a80
diff --git a/scripts/generate_source.py b/scripts/generate_source.py
index 3e3e315..db350c6 100755
--- a/scripts/generate_source.py
+++ b/scripts/generate_source.py
@@ -19,7 +19,6 @@
 # Author: Mike Schuchardt <mikes@lunarg.com>
 
 import argparse
-import common_codegen
 import filecmp
 import os
 import shutil
@@ -27,6 +26,8 @@
 import sys
 import tempfile
 
+import common_codegen
+
 # files to exclude from --verify check
 verify_exclude = ['.clang-format']
 
@@ -84,10 +85,7 @@
     for cmd in gen_cmds:
         print(' '.join(cmd))
         try:
-            subprocess.check_call([sys.executable] + cmd,
-                                  # ignore generator output, vk_validation_stats.py is especially noisy
-                                  stdout=subprocess.DEVNULL,
-                                  cwd=gen_dir)
+            subprocess.check_call([sys.executable] + cmd, cwd=gen_dir)
         except Exception as e:
             print('ERROR:', str(e))
             return 1