Fix bugs in simplified lowering relating to int32/uint32 signs.

test/cctest/compiler/test-instruction.cc

Index: test/cctest/compiler/test-instruction.cc
diff --git a/test/cctest/compiler/test-instruction.cc b/test/cctest/compiler/test-instruction.cc
index 425a46ced0930fe5d660d7679690426343c78eed..3e2b857f39abb00e5370ad9cf1e6d51e7feba870 100644
--- a/test/cctest/compiler/test-instruction.cc
+++ b/test/cctest/compiler/test-instruction.cc
@@ -33,6 +33,7 @@ class InstructionTester : public HandleAndZoneScope {
         info(static_cast<HydrogenCodeStub*>(NULL), main_isolate()),
         linkage(zone(), &info),
         common(zone()),
+        machine(zone()),
         code(NULL) {}
 
   ~InstructionTester() { delete code; }