Improve the casing of Stackmap and Stacktrace.

runtime/vm/snapshot.h

Index: runtime/vm/snapshot.h
diff --git a/runtime/vm/snapshot.h b/runtime/vm/snapshot.h
index 7bc946fb050b54dc8dd82890f69c2ed85438a4e2..c81098e8c236c4b2bf4c1af9f75e153e75175ac3 100644
--- a/runtime/vm/snapshot.h
+++ b/runtime/vm/snapshot.h
@@ -79,8 +79,8 @@ class RawRedirectionData;
 class RawScript;
 class RawSendPort;
 class RawSmi;
-class RawStackmap;
-class RawStacktrace;
+class RawStackMap;
+class RawStackTrace;
 class RawSubtypeTestCache;
 class RawTokenStream;
 class RawTwoByteString;
@@ -958,7 +958,7 @@ class SnapshotWriter : public BaseWriter {
   friend class RawReceivePort;
   friend class RawRegExp;
   friend class RawScript;
-  friend class RawStacktrace;
+  friend class RawStackTrace;
   friend class RawSubtypeTestCache;
   friend class RawTokenStream;
   friend class RawType;