Add a test for creating a VM without a config.

test/api/new_vm.c

@@ -0,0 +1,21 @@
+#include <string.h>
+
+#include "new_vm.h"
+
+static void nullConfig(WrenVM* vm)
+{
+  WrenVM* otherVM = wrenNewVM(NULL);
+  
+  // We should be able to execute code.
+  WrenInterpretResult result = wrenInterpret(otherVM, "1 + 2");
+  wrenSetSlotBool(vm, 0, result == WREN_RESULT_SUCCESS);
+  
+  wrenFreeVM(otherVM);
+}
+
+WrenForeignMethodFn newVMBindMethod(const char* signature)
+{
+  if (strcmp(signature, "static VM.nullConfig()") == 0) return nullConfig;
+
+  return NULL;
+}