Remove unused MethodInspectionCallback declaration

Addresses code review comment.

Test: make
Change-Id: I8ee9b83989d24e89d3987a1bf754fb7ab23a2abc
diff --git a/runtime/runtime.h b/runtime/runtime.h
index ac84d32..d71123d 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -92,7 +92,6 @@
 class IsMarkedVisitor;
 class JavaVMExt;
 class LinearAlloc;
-class MethodInspectionCallback;
 class MonitorList;
 class MonitorPool;
 class NullPointerHandler;