liblog: mark tests as require_root: true

Some tests require root to be run, so we require_root to run all of
them.

Test: tests pass as root
Change-Id: I5b3ca4f08e41f16e81c5d5995043ab55d379a882
diff --git a/liblog/tests/Android.bp b/liblog/tests/Android.bp
index 50800c5..2a6424b 100644
--- a/liblog/tests/Android.bp
+++ b/liblog/tests/Android.bp
@@ -72,6 +72,7 @@
     ],
     static_libs: ["liblog"],
     isolated: true,
+    require_root: true,
 }
 
 // Build tests for the device (with .so). Run with: