Make HForeignCode 'isAllocation' property available to optimization

pkg/compiler/lib/src/ssa/optimize.dart

Index: pkg/compiler/lib/src/ssa/optimize.dart
diff --git a/pkg/compiler/lib/src/ssa/optimize.dart b/pkg/compiler/lib/src/ssa/optimize.dart
index 0692383acd7320c1f05fc5fd1473c87f5f496630..d6da1985f7c1d6b0b3cc7671a3ff09e56d5cdc4c 100644
--- a/pkg/compiler/lib/src/ssa/optimize.dart
+++ b/pkg/compiler/lib/src/ssa/optimize.dart
@@ -1900,6 +1900,9 @@ class SsaLoadElimination extends HBaseVisitor implements OptimizationPhase {
   }
 
   void visitInstruction(HInstruction instruction) {
+    if (instruction.isAllocation()) {
+      memorySet.registerAllocation(instruction);
+    }
     memorySet.killAffectedBy(instruction);
   }