vcs: fix resources deallocation of simulation (#300)

When running with --workload-lilst, simv_init is reinitialized multiple times in a single launch, and the pointer from the last simv_init request needs to be destroyed before doing so. 

This commit fixed an issue with incomplete memory deallocation when exiting the program, and release the list file correctly when using the workload list

src/test/csrc/vcs/vcs_main.cpp

@@ -82,9 +82,11 @@ int switch_workload() {
       set_max_instrs(num);
     } else if (feof(fp)) {
       printf("Workload list is completed\n");
+      fclose(fp);
       return 1;
     } else {
       printf("Unknown workload list format\n");
+      fclose(fp);
       return 1;
     }
   } else {
@@ -177,12 +179,21 @@ void difftest_deferred_result(uint8_t result) {
 }
 #endif // CONFIG_DIFFTEST_DEFERRED_RESULT
 
+void simv_finish() {
+  common_finish();
+  flash_finish();
+  if (enable_difftest) {
+    goldenmem_finish();
+    difftest_finish();
+  }
+  delete simMemory;
+  simMemory = nullptr;
+}
+
 static uint8_t simv_result = SIMV_RUN;
 #ifdef CONFIG_DIFFTEST_DEFERRED_RESULT
 extern "C" void simv_nstep(uint8_t step) {
-  if (simv_result == SIMV_FAIL)
-    return;
-  if (difftest == NULL)
+  if (simv_result == SIMV_FAIL || difftest == NULL)
     return;
 #else
 extern "C" uint8_t simv_nstep(uint8_t step) {
@@ -200,7 +211,7 @@ extern "C" uint8_t simv_nstep(uint8_t step) {
     int ret = simv_step();
     if (ret) {
       simv_result = ret;
-      difftest_finish();
+      simv_finish();
 #ifdef CONFIG_DIFFTEST_DEFERRED_RESULT
       difftest_deferred_result(ret);
       return;