Fix delete operator with global variables (#1070)

Cherry-pick of bellard/quickjs@2d4e1cc.

Co-authored-by: Fabrice Bellard <fabrice@bellard.org>

Author: past-due

quickjs.c

@@ -10124,6 +10124,29 @@ static int JS_SetGlobalVar(JSContext *ctx, JSAtom prop, JSValue val,
     return JS_SetPropertyInternal(ctx, ctx->global_obj, prop, val, flags);
 }
 
+/* return -1, false or true */
+static int JS_DeleteGlobalVar(JSContext *ctx, JSAtom prop)
+{
+    JSObject *p;
+    JSShapeProperty *prs;
+    JSProperty *pr;
+    int ret;
+
+    /* 9.1.1.4.7 DeleteBinding ( N ) */
+    p = JS_VALUE_GET_OBJ(ctx->global_var_obj);
+    prs = find_own_property(&pr, p, prop);
+    if (prs)
+        return false; /* lexical variables cannot be deleted */
+    ret = JS_HasProperty(ctx, ctx->global_obj, prop);
+    if (ret < 0)
+        return -1;
+    if (ret) {
+        return JS_DeleteProperty(ctx, ctx->global_obj, prop, 0);
+    } else {
+        return true;
+    }
+}
+
 /* return -1, false or true. return false if not configurable or
    invalid object. return -1 in case of exception.
    flags can be 0, JS_PROP_THROW or JS_PROP_THROW_STRICT */
@@ -18669,7 +18692,7 @@ static JSValue JS_CallInternal(JSContext *caller_ctx, JSValueConst func_obj,
                 pc += 4;
 
                 sf->cur_pc = pc;
-                ret = JS_DeleteProperty(ctx, ctx->global_obj, atom, 0);
+                ret = JS_DeleteGlobalVar(ctx, atom);
                 if (unlikely(ret < 0))
                     goto exception;
                 *sp++ = js_bool(ret);