Add liblog as a dependency of libperfetto_client_experimental.

It has always been a dependency, but it is now being flagged when
compiling against stubs of liblog.

Test: buildbot-build.sh with master-art manifest
Bug: 170454179
Change-Id: I224bad2642c726131b77a4a7d1e798db6e59e0a6
diff --git a/Android.bp b/Android.bp
index b9638b1..c1a92ef 100644
--- a/Android.bp
+++ b/Android.bp
@@ -672,6 +672,9 @@
     ":perfetto_src_tracing_platform_posix",
     ":perfetto_src_tracing_system_backend",
   ],
+  shared_libs: [
+    "liblog",
+  ],
   export_include_dirs: [
     "include",
     "include/perfetto/base/build_configs/android_tree",