Add Vector type to Kernel

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 642 matching lines @@
 type LoadLibrary extends Expression {
   Byte tag = 14;
   DeferredImportReference import;
 }
 
 type CheckLibraryIsLoaded extends Expression {
   Byte tag = 13;
   DeferredImportReference import;
 }
 
+type VectorCreation extends Expression {
+  Byte tag = 102;
+  UInt length;
+}
+
+type VectorGet extends Expression {
+  Byte tag = 103;
+  Expression vectorExpression;
+  UInt index;
+}
+
+type VectorSet extends Expression {
+  Byte tag = 104;
+  Expression vectorExpression;
+  UInt index;
+  Expression value;
+}
+
+type VectorCopy extends Expression {
+  Byte tag = 105;
+  Expression vectorExpression;
+}
+
 abstract type Statement extends Node {}
 
 type InvalidStatement extends Statement {
   Byte tag = 60;
 }
 
 type ExpressionStatement extends Statement {
   Byte tag = 61;
   Expression expression;
 }
@@ skipping 236 matching lines @@
   // scope there.
   //
   // The type parameter can be bound by a Class, FunctionNode, or FunctionType.
   //
   // Note that constructors currently do not declare type parameters.  Uses of
   // the class type parameters in a constructor refer to those declared on the
   // class.
   UInt index;
 }
 
+type VectorType extends DartType {
+  Byte tag = 88;
+}
+
 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.
 }
 
 /* enum BaseClassKind { None, Exact, Subclass, Subtype, } */
 
 type InferredValue {
   ClassReference baseClass; // May be NullReference if kind = None.
   Byte kind; // Index into BaseClassKind.
   Byte valueBits; // See lib/type_propagation/type_propagation.dart
 }
 
 ```