[9] RFR(S): 8040085: dtrace/jsdt tests crash on solaris. found an unadvertised bad scavengable oop in the code cache

[Albert]

Hi,

could I get reviews for this small patch?

Bug: https://bugs.openjdk.java.net/browse/JDK-8040085

Problem: JDK-7017732 added 'CodeCache::add_scavenge_root_nmethod(this)' 
to the constructors of nmethod,
except for the dtrace-constructor version.

Solution: Add CodeCache::add_scavenge_root_nmethod(this) to the 
dtrace-constructor of nmethod.

Testing: Failing test case

Webrev: http://cr.openjdk.java.net/~anoll/8040085/webrev.00/

Many thanks in advance,
Albert