Remove SSE2 feature checks from x64 code (it is always on)

src/x64/assembler-x64.cc

Index: src/x64/assembler-x64.cc
diff --git a/src/x64/assembler-x64.cc b/src/x64/assembler-x64.cc
index 57d40f7946879014d61b254255df0e18d572f3c2..eee1584cf1fa5c34e870568f8b58b8672a47b0a1 100644
--- a/src/x64/assembler-x64.cc
+++ b/src/x64/assembler-x64.cc
@@ -150,9 +150,8 @@ void CpuFeatures::Probe() {
   found_by_runtime_probing_only_
       = probed_features & ~kDefaultCpuFeatures & ~platform_features;
 
-  // SSE2 and CMOV must be available on an X64 CPU.
+  // CMOV must be available on an X64 CPU.
   ASSERT(IsSupported(CPUID));
-  ASSERT(IsSupported(SSE2));
   ASSERT(IsSupported(CMOV));
 
   delete memory;