Break typecheck dependency in escape analysis.

src/hydrogen-escape-analysis.cc

Index: src/hydrogen-escape-analysis.cc
diff --git a/src/hydrogen-escape-analysis.cc b/src/hydrogen-escape-analysis.cc
index 3300f0b1bf7da655ec5c3e53dc3a4be2bc03536e..4a1e65d8562510593d04a28a160eb0828cc65aaa 100644
--- a/src/hydrogen-escape-analysis.cc
+++ b/src/hydrogen-escape-analysis.cc
@@ -212,7 +212,14 @@ void HEscapeAnalysisPhase::AnalyzeDataFlow(HInstruction* allocate) {
           if (mapcheck->value() != allocate) continue;
           // TODO(mstarzinger): This approach breaks if the tracked map value
           // is not a HConstant. Find a repro test case and fix this.
+          for (HUseIterator it(mapcheck->uses()); !it.Done(); it.Advance()) {
+            if (!it.value()->IsLoadNamedField()) continue;
+            HLoadNamedField* load = HLoadNamedField::cast(it.value());
+            ASSERT(load->typecheck() == mapcheck);
+            load->clear_typecheck();
+          }
           ASSERT(mapcheck->HasNoUses());
+
           mapcheck->DeleteAndReplaceWith(NULL);
           break;
         }