Move file_contexts for APEXes to under /system/sepolicy

For centralized development of sepolices, file_contexts files for APEXes
are all moved to under /system/seplicy.

Bug: 119034475
Bug: 113373927
Test: m apex.test com.android.tzdata com.android.runtime com.android.media
Change-Id: I9bf4874793db4dbdb75cbd759ae95f72d7281007
diff --git a/apex/apex.test_file_contexts b/apex/apex.test_file_contexts
new file mode 100644
index 0000000..bd71a2a
--- /dev/null
+++ b/apex/apex.test_file_contexts
@@ -0,0 +1,2 @@
+/manifest\.json   u:object_r:system_file:s0
+(/.*)?            u:object_r:system_file:s0