[Bug]: Coverage is broken for js_test when --experimental_split_coverage_postprocessing is defined

[ceyxiang]

What happened?

Hi! I made a copy of the tests in https://github.com/aspect-build/rules_js/tree/main/examples/coverage and tried to run coverage on the tests. Coverage would fail with this error message

==================== Test output for //:coverage:
FATAL: the entry_point '/home/christopher.eng/.cache/bazel/_bazel_christopher.eng/3c1075992044037b8e52b66729be4c8b/sandbox/linux-sandbox/3/execroot/temp_name/bazel-out/k8-fastbuild/bin/coverage_test/coverage.sh.runfiles/temp_name/../aspect_rules_js/js/private/coverage/coverage.js' not found in runfiles================================================================================

Coverage would run fine when I disabled --experimental_split_coverage_postprocessing in my .bazelrc

Version

Development (host) and target OS/architectures: Ubuntu 20.04 x86_64

Output of bazel --version:bazel 6.0.0

Version of the Aspect rules, or other relevant rules from your
WORKSPACE or MODULE.bazel file:

• aspect_rules_js: 1.15.1
• aspect_bazel_lib: 1.23.3
• aspect_rules_jest: 0.15.0

Language(s) and/or frameworks involved: Javascript

How to reproduce

I made a local copy of https://github.com/aspect-build/rules_js/tree/main/examples/coverage and ran


bazel coverage //example:coverage

and the error would occur

### Any other information?

[Slack thread where I initially raised the issue](https://bazelbuild.slack.com/archives/CEZUUKQ6P/p1675932171242519)

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