Closes Issue333 bisect extraneous runs

[JohnJacobsonIII]

Fixes #

Description:

Fix for bug that caused ground truth executable to be re-tested on every make call.

Bug originated from labeling executables as PHONY in Makefile.in; as a result all targets depending on the executable run every time make is called

Per @mikebentley15, a simple hack adding a layer of separation fixed the issue. The executable is no longer marked PHONY, but is a target with a single-use PHONY prerequisite and a no-op recipe. This still forces recursive calls to build every executable, but doesn't force dependents to run. The no-op recipe also forces Make to verify the timestamp on the executable.

Documentation:

No functionality changed, so no need for documentation changes.

Tests:

• Added unit test for ground truth re-test specifically. This should probably be expanded to test for more duplication (duplication of any test call, build stage, or anything else...)
• Required update to existing tst_incremental_build.py. Because of the no-op recipe, the executable is touched on every call; however, Make successfully determines that it doesn't need to be built, so this is simply a test methodology issue. The current fix is a hack, but the test needs to be rewritten to properly test makefile (by actually checking modification times.) I'll create an issue for this.

[JohnJacobsonIII]

Issue #338 opened to fix tst_incremental_build.py. Temporary hack here does not effectively test the incremental build, but the change here should not affect compilation so I've moved the fix to a separate issue.