Add fileEndOffset to Class.

pkg/kernel/binary.md

 This file describes the binary format of Dart Kernel.
 
 Notation
 --------
 Bitmasks are described with the syntax:
 ```scala
     Byte flags (flag1, flag2, ..., flagN)
 ```
 where 'flag<N>' is the N-th least significant bit,
 (so flag1 is the least significant bit).
@@ skipping 205 matching lines @@
 // If the enclosing library is external, a class is either at type or
 // hierarchy level, depending on its isTypeLevel flag.
 // If the enclosing library is not external, a class is always at body level.
 //
 // See ClassLevel in ast.dart for the details of each loading level.
 
 abstract type Class extends Node {
   Byte tag = 2;
   CanonicalNameReference canonicalName;
   FileOffset fileOffset;
+  FileOffset fileEndOffset;
   Byte flags (isAbstract, xx); // Where xx is index into ClassLevel
   StringReference name;
   // An absolute path URI to the .dart file from which the class was created.
   UriReference fileUri;
   List<Expression> annotations;
   List<TypeParameter> typeParameters;
   Option<InterfaceType> superClass;
   Option<InterfaceType> mixedInType;
   List<InterfaceType> implementedClasses;
   List<Field> fields;
@@ skipping 777 matching lines @@
   Option<DartType> bound;
 }
 
 type TypeParameter {
   // Note: there is no tag on TypeParameter
   StringReference name; // Cosmetic, may be empty, not unique.
   DartType bound; // 'dynamic' if no explicit bound was given.
 }
 
 ```