hg: jdk/jdk14: 8236000: VM build without C2 fails

[vladimir.kozlov at oracle.com]

Changeset: 5d4bf79ce2cb
Author:    kvn
Date:      2019-12-18 12:32 -0800
URL:       https://hg.openjdk.java.net/jdk/jdk14/rev/5d4bf79ce2cb

8236000: VM build without C2 fails
Summary: C2 flags should be checked only when C2 is present.
Reviewed-by: kbarrett, thartmann

! src/hotspot/share/gc/shared/genCollectedHeap.cpp
! src/hotspot/share/gc/z/zRootsIterator.cpp
! src/hotspot/share/jvmci/jvmci_globals.cpp
! src/hotspot/share/runtime/deoptimization.cpp