Disable dexlayout_test on target.

Target doesn't have diff to compare output files.

Bug: 29921113
Test: mm test-art-target-gtest-dexlayout_test
Change-Id: I244c0c74214b780676283de1b309978667ff58e3
diff --git a/dexlayout/dexlayout_test.cc b/dexlayout/dexlayout_test.cc
index 1757548..42b64c3 100644
--- a/dexlayout/dexlayout_test.cc
+++ b/dexlayout/dexlayout_test.cc
@@ -72,6 +72,8 @@
 
 
 TEST_F(DexLayoutTest, FullPlainOutput) {
+  // Disable test on target.
+  TEST_DISABLED_FOR_TARGET();
   std::string error_msg;
   ASSERT_TRUE(Exec(&error_msg)) << error_msg;
 }