Fix exit codes in build/test scripts

Fix exit codes in build/test scripts

The use of goto :eof in numerous places in the build and test scripts is problematic.  If preceded by an echo or other command, it will overwrite the exit code and the script may return incorrectly.  This was happening for buildtest, masking a recent ycompilation error in one of the tests.

Change all of the goto :eof's to exit /b.