Switch to using language-specific diagnostic environment variable

Author: smowton

java/ql/integration-tests/all-platforms/java/diagnostics/no-build-system/test.py

@@ -3,6 +3,6 @@
 from diagnostics_test_utils import *
 
 os.mkdir("diagnostics")
-run_codeql_database_create([], lang="java", runFunction = runUnsuccessfully, db = None, extra_env = {"CODEQL_EXTRACTOR_DIAGNOSTIC_DIR": "diagnostics"})
+run_codeql_database_create([], lang="java", runFunction = runUnsuccessfully, db = None, extra_env = {"CODEQL_EXTRACTOR_JAVA_DIAGNOSTIC_DIR": "diagnostics"})
 
 check_diagnostics(test_dir = ".", diagnostics_dir = "diagnostics")