Revert "Revert "Add a coverage suffix to avoid Ninja file regene..."

Revert submission 3235973-revert-3207217-emma-flip-time-saver-BYWASVIMTD

Reason for revert: Rolling forward with a fix

Adding a coverage suffix for product_config.go too:

FAILED: ninja: 'out/soong/soong.sdv_core_cf.extra.variables', needed by 'out/soong/.intermediates/build/soong/product_config/product_config.json', missing and no known rule to make it
03:42:23 ninja failed with: exit status 1

Reverted changes: /q/submissionid:3235973-revert-3207217-emma-flip-time-saver-BYWASVIMTD

Change-Id: I74d0e3fda09b1367f3dbb939d4f47c4d09b3d51f