[turbofan] re-enable some tests for arm64.

test/cctest/compiler/test-simplified-lowering.cc

Index: test/cctest/compiler/test-simplified-lowering.cc
diff --git a/test/cctest/compiler/test-simplified-lowering.cc b/test/cctest/compiler/test-simplified-lowering.cc
index e67df9bfd8cabe4c7a413d31648c165371639b0a..0dc09df6cb85742d7a75d07d692b4f941df5314d 100644
--- a/test/cctest/compiler/test-simplified-lowering.cc
+++ b/test/cctest/compiler/test-simplified-lowering.cc
@@ -56,8 +56,6 @@ class SimplifiedLoweringTester : public GraphBuilderTester<ReturnType> {
 };
 
 
-#ifndef V8_TARGET_ARCH_ARM64
-// TODO(titzer): these result in a stub call that doesn't work on ARM64.
 // TODO(titzer): factor these tests out to test-run-simplifiedops.cc.
 // TODO(titzer): test tagged representation for input to NumberToInt32.
 TEST(RunNumberToInt32_float64) {
@@ -113,7 +111,6 @@ TEST(RunNumberToUint32_float64) {
     }
   }
 }
-#endif
 
 
 // Create a simple JSObject with a unique map.