RFR: Use STRONG barrier for EncodeISOArray

[Roman Kennke]

Missing EncodeISOArray in get_barrier_strength() leads to asserts
failing in CTW test.

diff -r 82b898d4e103 -r dd0d3e62843a
src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp	Wed Mar
06 21:59:59 2019 +0100
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp	Thu Mar
07 23:03:49 2019 +0100
@@ -3181,6 +3181,7 @@
       case Op_EncodeP:
       case Op_CastP2X:
       case Op_SafePoint:
+      case Op_EncodeISOArray:
         strength = STRONG;
         break;
       case Op_LoadB:


Makes the test pass. Ok?

Roman