Revert "Add implicit null and stack checks for x86"

It breaks cross compilation with x86_64.

This reverts commit 34e826ccc80dc1cf7c4c045de6b7f8360d504ccf.

Change-Id: I34ba07821fc0a022fda33a7ae21850957bbec5e7
diff --git a/runtime/fault_handler.h b/runtime/fault_handler.h
index 71c9977..026f5b9 100644
--- a/runtime/fault_handler.h
+++ b/runtime/fault_handler.h
@@ -43,10 +43,9 @@
   void HandleFault(int sig, siginfo_t* info, void* context);
   void AddHandler(FaultHandler* handler, bool generated_code);
   void RemoveHandler(FaultHandler* handler);
-  void GetMethodAndReturnPCAndSP(siginfo_t* siginfo, void* context, mirror::ArtMethod** out_method,
+  void GetMethodAndReturnPCAndSP(void* context, mirror::ArtMethod** out_method,
                                  uintptr_t* out_return_pc, uintptr_t* out_sp);
-  bool IsInGeneratedCode(siginfo_t* siginfo, void *context, bool check_dex_pc)
-                         NO_THREAD_SAFETY_ANALYSIS;
+  bool IsInGeneratedCode(void *context, bool check_dex_pc) NO_THREAD_SAFETY_ANALYSIS;
 
  private:
   std::vector<FaultHandler*> generated_code_handlers_;