chore: added extra variables owlbot kokoro configs (#652)

Author: daniel-sanche

.kokoro/common.cfg

@@ -16,10 +16,32 @@
 import synthtool.gcp as gcp
 import synthtool.languages.node as node
 import logging
+import os
 
 logging.basicConfig(level=logging.DEBUG)
 
 common_templates = gcp.CommonTemplates()
 templates = common_templates.node_library()
 s.copy(templates, excludes=[".github/auto-label.yaml"])
 node.fix_hermetic()
+
+
+# --------------------------------------------------------------------------
+# Modify test configs
+# --------------------------------------------------------------------------
+
+# add shared environment variables to test configs
+s.move(
+    ".kokoro/common_env_vars.cfg",
+    ".kokoro/common.cfg",
+    merge=lambda src, dst, _, : f"{dst}\n{src}",
+)
+for path, subdirs, files in os.walk(f".kokoro/continuous"):
+    for name in files:
+        if name == "common.cfg":
+            file_path = os.path.join(path, name)
+            s.move(
+                ".kokoro/common_env_vars.cfg",
+                file_path,
+                merge=lambda src, dst, _, : f"{dst}\n{src}",
+            )