Separate generated test utilities and the tests.

The enables a test target to use the generated test utilities without
including all the generated tests.

Bug: 150805665
Test: NNT_static
Change-Id: I58fbf949a03f8f0199b0893da41fc90b5b5c004e
Merged-In: I58fbf949a03f8f0199b0893da41fc90b5b5c004e
(cherry picked from commit c8ec03cfe3df057e9537097213cba67ab118bc90)
5 files changed