RFR (XS) 8238153: CTW: C2 (Shenandoah) compilation fails with "Unknown node in get_load_addr: CreateEx"

[Aleksey Shipilev]

Bug:
  https://bugs.openjdk.java.net/browse/JDK-8238153

CTW tests caught this failure. I believe CreateEx should just be explicitly excepted, for the same
reason we did JDK-8229350: CreateEx has no useful inputs for us. This patch is safe, because it does
what "default" case does in release bits anyway.

diff -r e7c4199e4d32 src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp  Mon Jan 27 09:58:27 2020 -0500
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp  Wed Jan 29 11:44:59 2020 +0100
@@ -1796,12 +1796,13 @@
     case Op_CallDynamicJava:
     case Op_CallLeaf:
     case Op_CallStaticJava:
     case Op_ConN:
     case Op_ConP:
     case Op_Parm:
+    case Op_CreateEx:
       return phase->igvn().zerocon(T_OBJECT);
     default:
 #ifdef ASSERT
       fatal("Unknown node in get_load_addr: %s", NodeClassNames[in->Opcode()]);
 #endif
       return phase->igvn().zerocon(T_OBJECT);

Testing: affected CTW tests; will run hotspot_gc_shenandoah before push

-- 
Thanks,
-Aleksey