[lldb-dotest] Print dotest.py invocation.

In order to debug a failing python test, you need to debug Python
instead of the wrapper. For a while I've been adding and removing this,
but I think it could be useful for everyone.

llvm-svn: 357554

lldb/utils/lldb-dotest/lldb-dotest.in

@@ -13,4 +13,5 @@ if __name__ == '__main__':
     cmd.extend(dotest_args)
     cmd.extend(wrapper_args)
     # Invoke dotest.py and return exit code.
+    print(' '.join(cmd))
     sys.exit(subprocess.call(cmd))