RFR(M): 8008555: Debugging code in compiled method sometimes leaks memory

[Roland Westrelin]

http://cr.openjdk.java.net/~roland/8008555/webrev.00/

Debugging code such as +VerifyOops sometimes need to allocate a message string dynamically, allocates it on the C-heap and let it leak when the compiled method is reclaimed. This reuses the CodeComments machinery for these strings. It was inspired by a comment Tom made during the review of "7153771: array bound check elimination for c1":

> The Assert instruction leaks memory, which I guess it ok.  Maybe there's some way it could rely on the CodeComments stuff to manage that storage?

Roland.