Check that Dart_CreateIsolate is given a correct kind of snapshot.

runtime/vm/snapshot.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_SNAPSHOT_H_
 #define RUNTIME_VM_SNAPSHOT_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/bitfield.h"
@@ skipping 146 matching lines @@
     kAppWithJIT,  // Full snapshot of core libraries and application. Has some
                   // code, but may compile in the future because we haven't
                   // necessarily included code for every function or to
                   // (de)optimize.
     kAppNoJIT,    // Full snapshot of core libraries and application. Has
                   // complete code for the application that never deopts. Will
                   // not compile in the future.
     kNone,        // dart_bootstrap/gen_snapshot
     kInvalid
   };
+  static const char* KindToCString(Kind kind);
 
   static const int kHeaderSize = 2 * sizeof(int64_t);
   static const int kLengthIndex = 0;
   static const int kSnapshotFlagIndex = 1;
 
   static const Snapshot* SetupFromBuffer(const void* raw_memory);
 
   // Getters.
   const uint8_t* content() const { OPEN_ARRAY_START(uint8_t, uint8_t); }
   intptr_t length() const {
@@ skipping 866 matching lines @@
  private:
   SnapshotWriter* writer_;
   bool as_references_;
 
   DISALLOW_COPY_AND_ASSIGN(SnapshotWriterVisitor);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_SNAPSHOT_H_