hg: jdk/sandbox: 8224247: AllocateOldGenAt fires assertion failure

[chris.hegarty at oracle.com]

Changeset: 1a7f82c98eee
Author:    kkharbas
Date:      2019-06-03 11:04 -0700
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/1a7f82c98eee

8224247: AllocateOldGenAt fires assertion failure
Summary: Split the heap_reserved_size_bytes() into two methods - one for use during heap initialization and other for at later stages.
Reviewed-by: sangheki, tschatzl

! src/hotspot/share/gc/g1/g1Arguments.cpp
! src/hotspot/share/gc/g1/g1Arguments.hpp
! src/hotspot/share/gc/g1/heapRegionManager.cpp
! src/hotspot/share/gc/parallel/adjoiningGenerationsForHeteroHeap.cpp
! src/hotspot/share/gc/parallel/parallelArguments.cpp
! src/hotspot/share/gc/parallel/parallelArguments.hpp
! src/hotspot/share/prims/whitebox.cpp