Fix coverage.py under Windows

The windows bots can't find autoninja.bat, e.g. https://ci.chromium.org/ui/p/chromium/builders/ci/ToTWindowsCoverage/26941/overview.

Bug: 1453678
Change-Id: I3a0943c98f0e5e9d5bb9998b1475b8a58c0c89d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4778922
Reviewed-by: Nico Weber <[email protected]>
Commit-Queue: Arthur Eubanks <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1183974}
diff --git a/tools/code_coverage/coverage.py b/tools/code_coverage/coverage.py
index 15b4e88..e622653d 100755
--- a/tools/code_coverage/coverage.py
+++ b/tools/code_coverage/coverage.py
@@ -363,7 +363,7 @@
     subprocess_cmd.append('-j' + str(jobs_count))
 
   subprocess_cmd.extend(targets)
-  subprocess.check_call(subprocess_cmd)
+  subprocess.check_call(subprocess_cmd, shell=os.name == 'nt')
   logging.debug('Finished building %s.', str(targets))