[libc++] Fix %{temp} replacements when running benchmarks

Author: philnik777

libcxx/utils/libcxx/test/format.py

@@ -361,7 +361,7 @@ def execute(self, test, litConfig):
             if "enable-benchmarks=run" in test.config.available_features:
                 steps += ["%dbg(EXECUTED AS) %{exec} %t.exe --benchmark_out=%{temp}/benchmark-result.json --benchmark_out_format=json"]
                 parse_results = os.path.join(LIBCXX_UTILS, 'parse-google-benchmark-results')
-                steps += [f"{parse_results} %{temp}/benchmark-result.json --output-format=lnt > %{temp}/results.lnt"]
+                steps += [f"{parse_results} %{{temp}}/benchmark-result.json --output-format=lnt > %{{temp}}/results.lnt"]
             return self._executeShTest(test, litConfig, steps)
         elif re.search('[.]gen[.][^.]+$', filename): # This only happens when a generator test is not supported
             return self._executeShTest(test, litConfig, [])