Add test config template for sh_test.

Verification of compatibility with existing sh_test targets is in progress.

Bug: 148805488
Bug: 151761373

Test: make
Test: unit tests
Test: verified test config auto-gen for bc-tests and toybox-tests
Change-Id: Id8ce5dd0723e8c95921e2e20bff72fc828d47d87
Merged-In: Id8ce5dd0723e8c95921e2e20bff72fc828d47d87