vbscript: Skip the first (null) instruction in dump_code.

dlls/vbscript/compile.c

@@ -98,7 +98,8 @@ static void dump_code(compile_ctx_t *ctx)
 {
     instr_t *instr;
 
-    for(instr = ctx->code->instrs; instr < ctx->code->instrs+ctx->instr_cnt; instr++) {
+    for(instr = ctx->code->instrs+1; instr < ctx->code->instrs+ctx->instr_cnt; instr++) {
+        assert(instr->op < OP_LAST);
         TRACE_(vbscript_disas)("%d:\t%s", (int)(instr-ctx->code->instrs), instr_info[instr->op].op_str);
         dump_instr_arg(instr_info[instr->op].arg1_type, &instr->arg1);
         dump_instr_arg(instr_info[instr->op].arg2_type, &instr->arg2);