[parser] Use cached ThisExpression in this.x

..., this.x(), this.?x and this?.x(). For common
case like these, it's not necessary to store the
source position for the ThisExpression. And we
could use the cached kNoSourcePosition ThisExpression
for these.

Bug: v8:10914
Change-Id: I02e2bc1633f6da036535d7a76bdabeac0d22f4d9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3585490Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: 王澳 <wangao.james@bytedance.com>
Cr-Commit-Position: refs/heads/main@{#79982}

src/parsing/parser-base.h

@@ -1948,6 +1948,11 @@ ParserBase<Impl>::ParsePrimaryExpression() {
 
     case Token::THIS: {
       Consume(Token::THIS);
+      // Not necessary for this.x, this.x(), this?.x and this?.x() to
+      // store the source position for ThisExpression.
+      if (peek() == Token::PERIOD || peek() == Token::QUESTION_PERIOD) {
+        return impl()->ThisExpression();
+      }
       return impl()->NewThisExpression(beg_pos);
     }