Pass plusargs to VCS in execution phase
This fixes `test_plusargs` test case with VCS where plusargs would be
missing from from `cocotb.plusargs`.
@@ -82,7 +82,7 @@ $(COCOTB_RESULTS_FILE): $(SIM_BUILD)/simv $(CUSTOM_SIM_DEPS)
$(RM) $(COCOTB_RESULTS_FILE)
MODULE=$(MODULE) TESTCASE=$(TESTCASE) TOPLEVEL=$(TOPLEVEL) TOPLEVEL_LANG=$(TOPLEVEL_LANG) \
- $(SIM_CMD_PREFIX) $(SIM_BUILD)/simv +define+COCOTB_SIM=1 $(SIM_ARGS) $(EXTRA_ARGS)
+ $(SIM_CMD_PREFIX) $(SIM_BUILD)/simv +define+COCOTB_SIM=1 $(SIM_ARGS) $(EXTRA_ARGS) $(PLUSARGS)
$(call check_for_results_file)
