Account for building with GCC 10: JDK-8224851, -fcommon switch
    
    - GCC 10 turns on -fno-common by default, breaking the HotSpot build
    - There is a duplicate declaration of 'using MacroAssembler::call_VM_leaf_base'
      in interp_masm_aarch64.hpp which GCC 10 doesn't like anymore.
      Backport of JDK-8224851 fixes that.
    - Update to January 2020 CPU sources (11.0.6+10).
    - Switch to GA mode.
    - Add JDK-8236039 backport to resolve OpenShift blocker.
    - Add JDK-8224851 backport to resolve AArch64 compiler issues.
    
    Contributed-by: Andrew Hughes <gnu.andrew@redhat.com>