Revert "Revert "Enable ThinLTO for libvixl""

The new clang prebuild has fixed the miscompile issue.

Test: Build
Bug: 62839002
This reverts commit 145b179f133356f232b47c3c1fdd9f3528594417.

Change-Id: I18e65e7a8eac3f830f4aa2fb843842e1c14a1adf
diff --git a/Android.bp b/Android.bp
index 8f1c4ae..650b56b 100644
--- a/Android.bp
+++ b/Android.bp
@@ -133,7 +133,14 @@
         instrumentation: true,
         profile_file: "art/dex2oat.profdata",
         benchmarks: ["dex2oat"],
-    }
+    },
+    target: {
+        android: {
+            lto: {
+                 thin: true,
+            },
+        },
+    },
 }
 
 cc_library {
@@ -153,7 +160,14 @@
         instrumentation: true,
         profile_file: "art/dex2oat.profdata",
         benchmarks: ["dex2oat"],
-    }
+    },
+    target: {
+        android: {
+            lto: {
+                 thin: true,
+            },
+        },
+    },
 }
 
 cc_library {