VM: [DBC] Fix lazy deoptimization after calls that return no values.

runtime/vm/deopt_instructions.cc

Index: runtime/vm/deopt_instructions.cc
diff --git a/runtime/vm/deopt_instructions.cc b/runtime/vm/deopt_instructions.cc
index 31f08cd392432a4d0355c72d0ca10390e2b3f215..345db49623f3a3f101a6133ec1a0eebf84f909c5 100644
--- a/runtime/vm/deopt_instructions.cc
+++ b/runtime/vm/deopt_instructions.cc
@@ -1077,7 +1077,13 @@ void DeoptInfoBuilder::AddCopy(Value* value,
     deopt_instr = new (zone()) DeoptMaterializedObjectRefInstr(index);
   } else {
     ASSERT(!source_loc.IsInvalid());
-    switch (value->definition()->representation()) {
+#if defined(TARGET_ARCH_DBC)
+    Representation rep =
+        (value == NULL) ? kTagged : value->definition()->representation();
+#else
+    Representation rep = value->definition()->representation();
+#endif
+    switch (rep) {
       case kTagged:
         deopt_instr =
             new (zone()) DeoptWordInstr(ToCpuRegisterSource(source_loc));