RFR [11]: Fix clang build warnings

[Aleksey Shipilev]

sh/jdk11 specific fix for &&/|| precedence:

> diff -r 56be00244479 src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
> --- a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp  Thu Nov 01 12:23:30 2018 +0100
> +++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp  Thu Nov 01 16:36:25 2018 +0100
> @@ -3385,11 +3385,11 @@
>  
>  int ShenandoahEnqueueBarrierNode::needed(Node* n) {
>    if (n == NULL ||
>        n->is_Allocate() ||
>        n->bottom_type() == TypePtr::NULL_PTR ||
> -      n->bottom_type()->make_oopptr() != NULL && n->bottom_type()->make_oopptr()->const_oop() != NULL) {
> +      (n->bottom_type()->make_oopptr() != NULL && n->bottom_type()->make_oopptr()->const_oop() != NULL)) {
>      return NotNeeded;
>    }
>    if (n->is_Phi() ||
>        n->is_CMove()) {
>      return MaybeNeeded;
> diff -r 56be00244479 src/hotspot/share/opto/arraycopynode.cpp
> --- a/src/hotspot/share/opto/arraycopynode.cpp  Thu Nov 01 12:23:30 2018 +0100
> +++ b/src/hotspot/share/opto/arraycopynode.cpp  Thu Nov 01 16:36:25 2018 +0100
> @@ -311,11 +311,11 @@
>        return false;
>      }
>  
>      BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
>      if (dest_elem == T_OBJECT && (!is_alloc_tightly_coupled() ||
> -                                  bs->array_copy_requires_gc_barriers(T_OBJECT) SHENANDOAHGC_ONLY(&& !ShenandoahStoreValEnqueueBarrier))) {
> +         (bs->array_copy_requires_gc_barriers(T_OBJECT) SHENANDOAHGC_ONLY(&& !ShenandoahStoreValEnqueueBarrier)))) {
>        // It's an object array copy but we can't emit the card marking
>        // that is needed
>        return false;
>      }

Testing: Mac OS X builds

Thanks,
-Aleksey