G1 and Epsilon header cleanup for JDK-8282729

In JDK-8282729 a few headers where found which were indirectly included via `#include "gc/shared/blockOffsetTable.hpp", JDK-8282729 moves the Serial part of `blockOffsetTable` into `gc/serial` so those headers needs to be fixed for G1 and Epsilon. These header fixes were moved out of the issue to make the review processes easier. Here is a list of the files in question.
* `src/hotspot/share/gc/epsilon/epsilonHeap.hpp`
    * Uses `VirtualSpace`
* `src/hotspot/share/gc/g1/g1CollectionSetChooser.hpp`
    * Uses `G1MixedGCLiveThresholdPercent`
* `src/hotspot/share/gc/g1/g1FullGCScope.cpp`
    * Uses `MarkSweepDeadRatio`
* `src/hotspot/share/gc/g1/g1HeapRegionEventSender.cpp`
    * Uses `UseG1GC`
* `src/hotspot/share/gc/g1/g1HeapSizingPolicy.cpp`
    * Uses `GCTimeRatio`, `G1ExpandByPercentOfAvailable`, `MaxHeapSize`, `MinHeapSize`, `MaxHeapFreeRatio`, `MinHeapFreeRatio`
* `src/hotspot/share/gc/g1/g1MemoryPool.cpp`
    * Uses `UseG1GC`
* `src/hotspot/share/gc/g1/g1NUMA.cpp`
    * Uses `AlwaysPreTouch`
* `src/hotspot/share/gc/g1/g1RegionToSpaceMapper.cpp`
    * Uses `AlwaysPreTouch`
* `src/hotspot/share/gc/g1/g1SegmentedArrayFreeMemoryTask.cpp`
    * Uses `G1RemSetFreeMemoryStepDurationMillis`