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

test/cctest/compiler/test-js-constant-cache.cc

Index: test/cctest/compiler/test-js-constant-cache.cc
diff --git a/test/cctest/compiler/test-js-constant-cache.cc b/test/cctest/compiler/test-js-constant-cache.cc
index 2a591c198e4e6fc5d2dc647efb86a739ea0361fa..8588f66f1f546f7a6161e0f5d9f04b6752bc19ab 100644
--- a/test/cctest/compiler/test-js-constant-cache.cc
+++ b/test/cctest/compiler/test-js-constant-cache.cc
@@ -22,7 +22,7 @@ class JSCacheTesterHelper {
         main_common_(zone),
         main_javascript_(zone),
         main_typer_(&main_graph_, MaybeHandle<Context>()),
-        main_machine_() {}
+        main_machine_(zone) {}
   Graph main_graph_;
   CommonOperatorBuilder main_common_;
   JSOperatorBuilder main_javascript_;