Set -Oz for all cc targets.

Bug: 71844955
Change-Id: Icb544bd8892aa6d1a4a7de577373798256870a58
diff --git a/Android.bp b/Android.bp
index 4dce6a3..6bf44b0 100644
--- a/Android.bp
+++ b/Android.bp
@@ -150,6 +150,7 @@
 cc_defaults {
   name: "perfetto_defaults",
   cflags: [
+    "-Oz",
     "-Wno-error=return-type",
     "-Wno-sign-compare",
     "-Wno-sign-promo",