Statically link missing libraries to libsurfaceflinger_unittest

Some targets do not have the library in their system or
vendor image so the test fails to run.

Fixes: 170341496
Test: atest -a libsurfaceflinger_unittest on cf_x86_64_phone-userdebug

Change-Id: I61e7702e6b36f218bebc7c87853001861a92741e
diff --git a/services/surfaceflinger/TimeStats/timestatsproto/Android.bp b/services/surfaceflinger/TimeStats/timestatsproto/Android.bp
index 9513cab..fae4e94 100644
--- a/services/surfaceflinger/TimeStats/timestatsproto/Android.bp
+++ b/services/surfaceflinger/TimeStats/timestatsproto/Android.bp
@@ -1,4 +1,4 @@
-cc_library_shared {
+cc_library {
     name: "libtimestats_proto",
     export_include_dirs: ["include"],