Fix failures after div support.

- We need to special case divide by -1 because of x86.
- Disable div test on arm64, which does not support div yet.

Change-Id: I07e137cb555a958b02a6c4070f296503b7e30bae
diff --git a/compiler/optimizing/codegen_test.cc b/compiler/optimizing/codegen_test.cc
index 6d4514f..47e9fa4 100644
--- a/compiler/optimizing/codegen_test.cc
+++ b/compiler/optimizing/codegen_test.cc
@@ -543,7 +543,11 @@
   }
 }
 
+#if defined(__aarch64__)
+TEST(CodegenTest, DISABLED_ReturnDivIntLit8) {
+#else
 TEST(CodegenTest, ReturnDivIntLit8) {
+#endif
   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
     Instruction::CONST_4 | 4 << 12 | 0 << 8,
     Instruction::DIV_INT_LIT8, 3 << 8 | 0,