Rename TEST_MODE to specific variable for CodeQL Action

This allows us to set it automatically in the workflow generator,
simplifying things and reducing the scope for error.

.github/workflows/__javascript-source-root.yml

@@ -52,8 +52,6 @@ jobs:
         languages: javascript
         source-root: ../new-source-root
         tools: ${{ steps.prepare-test.outputs.tools-url }}
-      env:
-        TEST_MODE: true
     - uses: ./../action/analyze
       with:
         skip-queries: true
@@ -68,3 +66,4 @@ jobs:
         fi
     env:
       INTERNAL_CODEQL_ACTION_DEBUG_LOC: true
+      CODEQL_ACTION_TEST_MODE: true