RFR: JDK-8214311 dtrace gensrc has missing dependencies

[Magnus Ihse Bursie]

Building with JOBS=1 on solaris discovered that the dtrace gensrc has 
not all dependencies properly declared. This has not been discovered 
until now, since Solaris machines is typically very parallel, and the 
needed prerequisites has just happened to have been generated before.

Bug: https://bugs.openjdk.java.net/browse/JDK-8214311
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8214311-fix-dtrace-gensrc-dependencies/webrev.01

/Magnus