RFR(XXL): 8079792: GC directory structure cleanup

[Per Liden]

Hi,

As previously mentioned [1], the GC team is doing a cleanup of the 
directory structure for the GC code. Here's the patch for that cleanup.

First, a recap of the new directory structure:

- A single "top-level" directory for GC code:
	src/share/vm/gc/

- One sub-directory per GC:
	src/share/vm/gc/cms/
	src/share/vm/gc/g1/
	src/share/vm/gc/parallel/
	src/share/vm/gc/serial/

- A single directory for common/shared GC code:
	src/share/gc/shared/


A number of GC files previously located in memory and utilities have 
been moved in under the gc directory (mostly into gc/shared), these are:

	memory/barrierSet.*
	memory/blockOffsetTable.*
	memory/cardGeneration.*
	memory/cardTableModRefBS.*
	memory/cardTableRS.*
	memory/collectorPolicy.*
	memory/gcLocker.*
	memory/genCollectedHeap.*
	memory/generation.*
	memory/generationSpec.*
	memory/genOopClosures.*
	memory/genMarkSweep.*
	memory/genRemSet.*
	memory/modRefBarrierSet.*
	memory/referencePolicy.*
	memory/referenceProcessor.*
	memory/referenceProcessorStats.*
	memory/space.*
	memory/specialized_oop_closures.*
	memory/strongRootsScope.*
	memory/tenuredGeneration.*
	memory/threadLocalAllocBuffer.*
	memory/watermark.*
	utilities/workgroup.*
	utilities/taskqueue.*


The patch is very large because it touches a lot of files, but the 
individual changes are trivial. The main bulk of the changes consists of 
adjustments to #includes "gc_implementation/... and #ifndef 
SHARE_VM_GC_IMPL... The rest (minor part) of the patch include 
adjustments to some makefiles, SA and jtreg tests.


Webrev: http://cr.openjdk.java.net/~pliden/8079792/webrev.0/

Here's the same webrev split into the following pieces:

- Change to cpp/hpp files
http://cr.openjdk.java.net/~pliden/8079792/webrev.0-hotspot/

- Changes to makefiles
http://cr.openjdk.java.net/~pliden/8079792/webrev.0-make/

- Changes to SA
http://cr.openjdk.java.net/~pliden/8079792/webrev.0-sa/

- Changes to jtreg tests
http://cr.openjdk.java.net/~pliden/8079792/webrev.0-test/


Bug: https://bugs.openjdk.java.net/browse/JDK-8079792

Testing: JPRT, Aurora adhoc GC nightly, bigapps

cheers,
/Per

[1] http://mail.openjdk.java.net/pipermail/hotspot-dev/2015-May/018439.html