[orderfile] Fix error reporting when compilation fails.

From https://logs.chromium.org/logs/chrome/buildbucket/cr-buildbucket/8837870616071893953/+/u/Generate_Orderfile/stdout

RunBenchmark at /b/swarming/w/ir/cache/builder/src/tools/cygprofile/orderfile_generator_backend.py:923
    benchmark_results['Error'] = str(e)
UnboundLocalError: local variable 'benchmark_results' referenced before assignment

Bug: 1186598
Change-Id: Idd35d559045903e61b88e7aa1ae436c88a2937bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3121428
Auto-Submit: Benoit L <lizeb@chromium.org>
Commit-Queue: Peter Kotwicz <pkotwicz@chromium.org>
Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#915565}

diff --git a/tools/cygprofile/orderfile_generator_backend.py b/tools/cygprofile/orderfile_generator_backend.py
index c8fdf79..c66963e6 100755
--- a/tools/cygprofile/orderfile_generator_backend.py
+++ b/tools/cygprofile/orderfile_generator_backend.py

@@ -894,6 +894,7 @@
     Returns:
       benchmark_results: (dict) Results extracted from benchmarks.
     """
+    benchmark_results = {}
     try:
       _UnstashOutputDirectory(out_directory)
       self._compiler = ClankCompiler(out_directory, self._step_recorder,
@@ -913,7 +914,6 @@
       self._compiler.CompileChromeApk(instrumented=False,
                                       use_call_graph=False,
                                       force_relink=True)
-      benchmark_results = dict()
       benchmark_results['Speedometer2.0'] = self._PerformanceBenchmark(
           self._compiler.chrome_apk)
       benchmark_results['orderfile.memory_mobile'] = (