Fix DUK_UNREF() position, cl issue

src/duk_debugger.c

@@ -1162,8 +1162,6 @@ DUK_LOCAL void duk__debug_handle_get_locals(duk_hthread *thr, duk_heap *heap) {
 DUK_LOCAL void duk__debug_handle_eval(duk_hthread *thr, duk_heap *heap) {
 	duk_context *ctx = (duk_context *) thr;
 
-	DUK_UNREF(heap);
-
 	duk_small_uint_t call_flags;
 	duk_int_t call_ret;
 	duk_small_int_t eval_err;
@@ -1171,6 +1169,8 @@ DUK_LOCAL void duk__debug_handle_eval(duk_hthread *thr, duk_heap *heap) {
 	duk_idx_t entry_top;
 #endif
 
+	DUK_UNREF(heap);
+
 	DUK_D(DUK_DPRINT("debug command eval"));
 
 	/* The eval code must be executed within the current (topmost)