Test METHOD_EXIT_WITH_RETURN_VALUE event on void method

Adds MethodExitWithReturnValueTest#testMethodExitWithReturnValueOfVoid test to
check we properly handle METHOD_EXIT_WITH_RETURN_VALUE event on void method. In
this case, there is no bytes to read for the return value.

Adds the handling of VOID tag in Packet.getNextValueAsUntaggedValue.

Change-Id: I38ba47456021cf85def7b53a1181d6b3e492d8b6