[lit] Improve error message when lit fails to executable a command by

showing the executable it tried to use.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253032 91177308-0d34-0410-b5e6-96231b3b80d8

utils/lit/lit/TestRunner.py

@@ -207,7 +207,7 @@ def executeShCmd(cmd, shenv, results):
                                           env = cmd_shenv.env,
                                           close_fds = kUseCloseFDs))
         except OSError as e:
-            raise InternalShellError(j, 'Could not create process due to {}'.format(e))
+            raise InternalShellError(j, 'Could not create process ({}) due to {}'.format(executable, e))
 
         # Immediately close stdin for any process taking stdin from us.
         if stdin == subprocess.PIPE: