Simplify scanner and generate better error message for legacy octals in templates

test/mjsunit/harmony/templates.js

Index: test/mjsunit/harmony/templates.js
diff --git a/test/mjsunit/harmony/templates.js b/test/mjsunit/harmony/templates.js
index e2e89dc67f4cf2e74d411bf8f40ffbf021a6bfdc..c339bb8cc7609f0eff03f84b85c790d036559ef1 100644
--- a/test/mjsunit/harmony/templates.js
+++ b/test/mjsunit/harmony/templates.js
@@ -476,9 +476,11 @@ var obj = {
 (function testLegacyOctal() {
   assertEquals('\u0000', `\0`);
   assertEquals('\u0000a', `\0a`);
-  for (var i = 0; i < 10; i++) {
+  for (var i = 0; i < 8; i++) {
     var code = "`\\0" + i + "`";
     assertThrows(code, SyntaxError);
+    code = "(function(){})" + code;
+    assertThrows(code, SyntaxError);
   }
 
   assertEquals('\\0', String.raw`\0`);
@@ -488,8 +490,18 @@ var obj = {
 (function testSyntaxErrorsNonEscapeCharacter() {
   assertThrows("`\\x`", SyntaxError);
   assertThrows("`\\u`", SyntaxError);
-  for (var i = 1; i < 10; i++) {
+  for (var i = 1; i < 8; i++) {
     var code = "`\\" + i + "`";
     assertThrows(code, SyntaxError);
+    code = "(function(){})" + code;
+    assertThrows(code, SyntaxError);
   }
 })();
+
+
+(function testValidNumericEscapes() {
+  assertEquals("8", `\8`);
+  assertEquals("9", `\9`);
+  assertEquals("\u00008", `\08`);
+  assertEquals("\u00009", `\09`);
+})();