build: allow Node 10 on presubmit to push to codecov (#700)

Author: bcoe

.kokoro/presubmit/node10/test.cfg

@@ -0,0 +1,9 @@
+# Bring in codecov.io master token into the build as $KOKORO_KEYSTORE_DIR/73713_dpebot_codecov_token
+before_action {
+  fetch_keystore {
+    keystore_resource {
+      keystore_config_id: 73713
+      keyname: "dpebot_codecov_token"
+    }
+  }
+}

.kokoro/presubmit/node8/test.cfg

@@ -1,9 +0,0 @@
-# Bring in codecov.io master token into the build as $KOKORO_KEYSTORE_DIR/73713_dpebot_codecov_token
-before_action {
-  fetch_keystore {
-    keystore_resource {
-      keystore_config_id: 73713
-      keyname: "dpebot_codecov_token"
-    }
-  }
-}