RFR(S) 8244775 Remove unnecessary dependency to jfrEvents.hpp

[Kim Barrett]

> On May 12, 2020, at 1:36 AM, Ioi Lam <ioi.lam at oracle.com> wrote:
> 
> https://bugs.openjdk.java.net/browse/JDK-8244775
> http://cr.openjdk.java.net/~iklam/jdk15/8244775-remove-dependency-jfrEvents.hpp.v01/
> 
> Currently 231 .o files depends on jfrEvents.hpp, which pulls in a lot of stuff
> and slows down HotSpot build.
> 
> I refactored compile.hpp, compilerEvent.hpp and g1GCPhaseTimes.hpp. Now the
> number is down to 65 .o files.
> 
> On my machine, debug build goes from 2m19s to 2m01s.
> 
> Testing: passed mach5 tiers 1/2/3.
> 
> Thanks
> - Ioi

GC changes look good.

There are some implicit includes that might be nice to address, but those are pretty much
pre-existing.  Consider adding utilities/ticks.hpp to g1GCParPhaseTimesTracker.hpp.