[V8] Reland https://codereview.chromium.org/1121833003/

src/scanner.cc

Index: src/scanner.cc
diff --git a/src/scanner.cc b/src/scanner.cc
index 3092e33da83b8663944ca508100857650a541da2..8405591dc82dd5b204e3d84398e66b80222e5474 100644
--- a/src/scanner.cc
+++ b/src/scanner.cc
@@ -236,6 +236,10 @@ static const byte one_char_tokens[] = {
 
 
 Token::Value Scanner::Next() {
+  if (next_.token == Token::EOS) {
+    next_.location.beg_pos = current_.location.beg_pos;
+    next_.location.end_pos = current_.location.end_pos;
+  }
   current_ = next_;
   has_line_terminator_before_next_ = false;
   has_multiline_comment_before_next_ = false;