Experimental parser: add UnicodeCache.

src/lexer/experimental-scanner.h

Index: src/lexer/experimental-scanner.h
diff --git a/src/lexer/experimental-scanner.h b/src/lexer/experimental-scanner.h
index 13484b5387f51b8105f7dd4eeff21f7a978d223a..5b117f97b406a76dfc60b4fe8e3769191cc24b21 100644
--- a/src/lexer/experimental-scanner.h
+++ b/src/lexer/experimental-scanner.h
@@ -54,7 +54,9 @@ class ExperimentalScanner {
     int end_pos;
   };
 
-  ExperimentalScanner(const char* fname, bool read_all_at_once);
+  ExperimentalScanner(const char* fname,
+                      bool read_all_at_once,
+                      Isolate* isolate);
   ~ExperimentalScanner();
 
   Token::Value Next();