Add a regression test for invalidating empty TB and have a better solution

uc.c

@@ -657,12 +657,6 @@ uc_err uc_emu_start(uc_engine *uc, uint64_t begin, uint64_t until,
     uc->timed_out = false;
     uc->first_tb = true;
 
-    // In this case, we don't do any emulation because it will generate
-    // an empty translation block which we can't invalidate.
-    if (begin == until) {
-        return UC_ERR_OK;
-    }
-
     switch (uc->arch) {
     default:
         break;