Fix a couple of bugs in sub_test for C tests

lastcompopts was not being added to C tests properly.

envExecopts was incorrectly being added to C test executions.
Merge pull request #380 from Kyle-B/c-tests-fix

Fix a couple of bugs in sub_test for C tests

lastcompopts was not being added to C tests properly.

envExecopts was incorrectly being added to C test executions.