Fix runfiles merging for @bazel_tools//tools/bash/runfiles

[fmeum]

Description

Fix merging of runfiles of @bazel_tools//tools/bash/runfiles.

Related Issue

Motivation and Context

This is required in Bazel 8.3.0, where this target gained runfiles.

How Has This Been Tested?

Covered by existing tests running on Bazel 8.3.0

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[kzadorozhny]

Thank you for the contribution. Could you please rebase on latest main for the CI to be able to run?