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/compiler/dex/quick/x86/codegen_x86.h b/compiler/dex/quick/x86/codegen_x86.h
index 7e77364..ff7b30e 100644
--- a/compiler/dex/quick/x86/codegen_x86.h
+++ b/compiler/dex/quick/x86/codegen_x86.h
@@ -85,7 +85,6 @@
   LIR* StoreBaseIndexedDisp(RegStorage r_base, RegStorage r_index, int scale, int displacement,
                             RegStorage r_src, OpSize size) OVERRIDE;
   void MarkGCCard(RegStorage val_reg, RegStorage tgt_addr_reg);
-  void GenImplicitNullCheck(RegStorage reg, int opt_flags);
 
   // Required for target - register utilities.
   RegStorage TargetReg(SpecialTargetRegister reg) OVERRIDE;
@@ -797,11 +796,9 @@
    * @param base_reg The register holding the base address.
    * @param offset The offset from the base.
    * @param check_value The immediate to compare to.
-   * @param target branch target (or nullptr)
-   * @param compare output for getting LIR for comparison (or nullptr)
    */
   LIR* OpCmpMemImmBranch(ConditionCode cond, RegStorage temp_reg, RegStorage base_reg,
-                         int offset, int check_value, LIR* target, LIR** compare);
+                         int offset, int check_value, LIR* target);
 
   /*
    * Can this operation be using core registers without temporaries?