Revert "Make output of run_tests.py easier to understand. (flutter#16229)"

This reverts commit 019473b.

Author: NoamDev

testing/run_tests.py

@@ -13,7 +13,6 @@
 import re
 import subprocess
 import sys
-import time
 
 buildroot_dir = os.path.abspath(os.path.join(os.path.realpath(__file__), '..', '..', '..'))
 out_dir = os.path.join(buildroot_dir, 'out')
@@ -25,34 +24,12 @@
 
 fml_unittests_filter = '--gtest_filter=-*TimeSensitiveTest*'
 
-def PrintDivider(char='='):
-  print '\n'
-  for _ in xrange(4):
-    print(''.join([char for _ in xrange(80)]))
-  print '\n'
-
 def RunCmd(cmd, **kwargs):
-  command_string = ' '.join(cmd)
-
-  PrintDivider('>')
-  print 'Running command "%s"' % command_string
-
-  start_time = time.time()
-  process = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, **kwargs)
-  (output, _) = process.communicate()
-  end_time = time.time()
-
-  # Print the result no matter what.
-  for line in output.splitlines():
-    print line
-
-  if process.returncode != 0:
-    PrintDivider('!')
-    raise Exception('Command "%s" exited with code %d' % (command_string, process.returncode))
-
-  PrintDivider('<')
-  print 'Command run successfully in %.2f seconds: %s' % (end_time - start_time, command_string)
-
+  try:
+    print(subprocess.check_output(cmd, **kwargs))
+  except subprocess.CalledProcessError as cpe:
+    print(cpe.output)
+    raise cpe
 
 def IsMac():
   return sys.platform == 'darwin'