Revert "Revert "[Cronet] Exclude spaceship operator<=> from cove..."

Revert submission 3031237-revert_v3

Reason for revert: Fixed in this cl. The issue was caused by not having `default:allow` in the exclude_coverage.list

Reverted changes: /q/submissionid:3031237-revert_v3

Change-Id: I2f8585c63e1a8ef35b5a256a5fecd8c69abd408e
4 files changed