[16] RFR(S): 8248398: Add diagnostic RepeatCompilation utility

[Nils Eliasson]

Hi,

This is a diagnostic utility that was requested by Claes to enable 
better profiling of the compilers.

This patch introduces the diagnostic flag RepeatCompilation.

RepeatCompilation hold he number of times the compilation gets repeated 
without having the code installed. RepeatCompilation = 0 is the default 
and means that only the regular compilation is done. RepeatCompilation = 
100 means that an extra 100 compilations are done but without installing 
the code.

I have tried keeping the change small and non-intrusive, contained to 
the CompilerBroker (except the boolean for disabling code install that 
is passed to the compilers).

RepatCompilation works as a flag: "-XX:RepeatCompilation=100", a compile 
command: "-XX:CompileCommand=option,*::toString,intx,RepeatCompilation,100"
and a compiler directive: "RepeatCompilation : 100".

Bug: https://bugs.openjdk.java.net/browse/JDK-8248398
Webrev: http://cr.openjdk.java.net/~neliasso/8248398/webrev.04/

Please review!

Best regards,
Nils Eliasson