No global ThinLTO for bionic

There are multiple build breakages with bionic when we enable ThinLTO
globally. Opt bionic out of ThinLTO for now.

#global-thinlto-opt-out

Test: TreeHugger
Bug: 169004486
Change-Id: I546a8074f9c3e0ddbd01d3b7cd730e215e3c0c49
diff --git a/libm/Android.bp b/libm/Android.bp
index 318a4bc..7f96975 100644
--- a/libm/Android.bp
+++ b/libm/Android.bp
@@ -506,6 +506,10 @@
         "//apex_available:platform",
         "com.android.runtime",
     ],
+
+    lto: {
+        never: true,
+    },
 }
 
 ndk_library {