Reland "[parser] Forbid \08 in strict strings"

src/parsing/scanner.cc

Index: src/parsing/scanner.cc
diff --git a/src/parsing/scanner.cc b/src/parsing/scanner.cc
index 351a1740e82a8aa5f3dd96e63db08a9533c18b14..20a53f3c988fd4c82a64c043e337330ac22211e3 100644
--- a/src/parsing/scanner.cc
+++ b/src/parsing/scanner.cc
@@ -1032,7 +1032,7 @@ uc32 Scanner::ScanOctalEscape(uc32 c, int length) {
   // can be reported later (in strict mode).
   // We don't report the error immediately, because the octal escape can
   // occur before the "use strict" directive.
-  if (c != '0' || i > 0) {
+  if (c != '0' || i > 0 || c0_ == '8' || c0_ == '9') {
     octal_pos_ = Location(source_pos() - i - 1, source_pos() - 1);
     octal_message_ = MessageTemplate::kStrictOctalEscape;
   }