RFR(XS): 8043063: Code aging should allocate MethodCounters when flushing a method

[Igor Veresov]

In some edge cases we may not have MethodCounters allocated for a method that was compiled, like with -Xcomp.
So with code aging we need to allocate MCs when we are flushing the method to set up the aging counter.

Webrev: http://cr.openjdk.java.net/~iveresov/8043063/webrev.00/

Thanks!
igor