Revert "Revert "Upgrade to 5.0.71.48"" DO NOT MERGE

This reverts commit f2e3994fa5148cc3d9946666f0b0596290192b0e,
and updates the x64 makefile properly so it doesn't break that
build.

FPIIM-449

Change-Id: Ib83e35bfbae6af627451c926a9650ec57c045605
(cherry picked from commit 109988c7ccb6f3fd1a58574fa3dfb88beaef6632)
diff --git a/src/x64/assembler-x64-inl.h b/src/x64/assembler-x64-inl.h
index bfec51c..9a0fc7c 100644
--- a/src/x64/assembler-x64-inl.h
+++ b/src/x64/assembler-x64-inl.h
@@ -456,10 +456,8 @@
   }
   if (write_barrier_mode == UPDATE_WRITE_BARRIER &&
       host() != NULL) {
-    // TODO(1550) We are passing NULL as a slot because cell can never be on
-    // evacuation candidate.
-    host()->GetHeap()->incremental_marking()->RecordWrite(
-        host(), NULL, cell);
+    host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(host(), this,
+                                                                  cell);
   }
 }
 
@@ -478,23 +476,6 @@
 }
 
 
-bool RelocInfo::IsPatchedReturnSequence() {
-  // The recognized call sequence is:
-  //  movq(kScratchRegister, address); call(kScratchRegister);
-  // It only needs to be distinguished from a return sequence
-  //  movq(rsp, rbp); pop(rbp); ret(n); int3 *6
-  // The 11th byte is int3 (0xCC) in the return sequence and
-  // REX.WB (0x48+register bit) for the call sequence.
-  return pc_[Assembler::kMoveAddressIntoScratchRegisterInstructionLength] !=
-         0xCC;
-}
-
-
-bool RelocInfo::IsPatchedDebugBreakSlotSequence() {
-  return !Assembler::IsNop(pc());
-}
-
-
 Handle<Object> RelocInfo::code_age_stub_handle(Assembler* origin) {
   DCHECK(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
   DCHECK(*pc_ == kCallOpcode);