Preserve stack map frames.

Preserve stack map frames for V51 and newer bytecode. This fixes class verification errors for JDK7 and JDK8. The option to disable bytecode verification was removed in JDK8.

This solves the same problem as the AsmInstrumentingClassLoader change in
robolectric#881, but the custom getCommonSuperClass implementation in that patch doesn't seem to work reliably.