Update PGO configuration

Bug: http://b/63768402

- Remove the 'enable_profile_use' property.  This is a no-op change with
https://android-review.googlesource.com/c/591562 - PGO profile use is
only enabled if the profile file exists.  We don't have one yet.
- Move the profile file location to an art/ subdirectory so it doesn't
conflict with profiles for other projects

Test: Build AOSP
Change-Id: Ifb7cded58a786dc5b1024a4c2c770873fcf4413c
diff --git a/compiler/Android.bp b/compiler/Android.bp
index d4d72f3..01f761b 100644
--- a/compiler/Android.bp
+++ b/compiler/Android.bp
@@ -252,9 +252,8 @@
 
     pgo: {
         instrumentation: true,
-        profile_file: "dex2oat.profdata",
+        profile_file: "art/dex2oat.profdata",
         benchmarks: ["dex2oat"],
-        enable_profile_use: false,
     }
 }