find_var_htab: skip entries with scope_level != 0

When a `var` shadows a block-scoped `let` of the same name,
find_var_htab returned the block-scoped entry. find_var rejected it
(scope_level != 0) and fell through to an O(n) linear scan.

Add scope_level == 0 check to the htab probe loop so non-scope-0
entries are skipped. This lets find_var treat htab miss as definitive.

Author: jiang1997

quickjs.c

@@ -23378,7 +23378,8 @@ static int find_var_htab(JSFunctionDef *fd, JSAtom var_name)
         p = &fd->vars_htab[i & m];
         if (*p == UINT32_MAX)
             return -1;
-        if (fd->vars[*p].var_name == var_name)
+        if (fd->vars[*p].var_name == var_name &&
+            fd->vars[*p].scope_level == 0)
             return *p;
         i += j;
         j += 1; // quadratic probing
@@ -23405,11 +23406,9 @@ static int find_var(JSContext *ctx, JSFunctionDef *fd, JSAtom name)
 
     if (fd->vars_htab) {
         i = find_var_htab(fd, name);
-        if (i == -1)
-            goto not_found;
-        vd = &fd->vars[i];
-        if (vd->scope_level == 0)
+        if (i >= 0)
             return i;
+        goto not_found;
     }
     for(i = fd->var_count; i-- > 0;) {
         vd = &fd->vars[i];