Merge pull request #6789 from jtattermusch/fix_make_options_propagation

Fix run_tests.py propagation of make options under docker
diff --git a/tools/run_tests/run_tests.py b/tools/run_tests/run_tests.py
index 0a5625c..f7282dd 100755
--- a/tools/run_tests/run_tests.py
+++ b/tools/run_tests/run_tests.py
@@ -254,9 +254,7 @@
 
   def _compiler_options(self, use_docker, compiler):
     """Returns docker distro and make options to use for given compiler."""
-    if _is_use_docker_child():
-      return ("already_under_docker", [])
-    if not use_docker:
+    if not use_docker and not _is_use_docker_child():
       _check_compiler(compiler, ['default'])
 
     if compiler == 'gcc4.9' or compiler == 'default':