RFR [8]: Fix build failure due to unknown INCLUDE_SHENANDOAHGC

[Roman Kennke]

Ugh. Yes, please do. Thanks for fixing.
Roman

> This changeset:
> 
> changeset:   11140:c2e689bdeaf8
> user:        rkennke
> date:        Thu Dec 06 13:27:58 2018 +0100
> summary:     JDK8u-only: Use WB-based acmp barrier
> 
> ...actually broke the sh/jdk8 build:
> 
> /home/buildbot/worker/shenandoah-jdk8-linux/build/hotspot/src/share/vm/opto/subnode.cpp:867:5:
> error: "INCLUDE_SHENANDOAHGC" is not defined [-Werror=undef]
>  #if INCLUDE_SHENANDOAHGC
>      ^~~~~~~~~~~~~~~~~~~~
> 
> ...and I haven't noticed it during backports, because I pulled that changeset only after backports
> testing was done. Argh.
> 
> Fix:
> 
> diff -r bd0a98b181a1 src/share/vm/opto/subnode.cpp
> --- a/src/share/vm/opto/subnode.cpp     Mon Dec 10 18:30:12 2018 +0100
> +++ b/src/share/vm/opto/subnode.cpp     Tue Dec 11 12:26:36 2018 +0100
> @@ -862,11 +862,11 @@
>  static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) {
>    // Return the klass node for
>    //   LoadP(AddP(foo:Klass, #java_mirror))
>    //   or NULL if not matching.
> 
> -#if INCLUDE_SHENANDOAHGC
> +#if INCLUDE_ALL_GCS
>    n = ShenandoahBarrierNode::skip_through_barrier(n);
>  #endif
> 
>    if (n->Opcode() != Op_LoadP) return NULL;
>    const TypeInstPtr* tp = phase->type(n)->isa_instptr();
> 
> Testing: hotspot_gc_shenandoah
> 
> -Aleksey
>