SEPolicy changes to allow vendor BoringSSL self test.

Introduces new domain vendor_boringssl_self_test and runs
/vendor/bin/boringssl_self_test(32|64) in it. New domain
required because boringssl_self_test needs to be in
coredomain in order to reboot the device, but vendor code
may not run in coredomain.

Bug: 141150335
Test: flashall && manually verify no selinux errors logged and that
    four flag files are created in /dev/boringssl, two by the
    system self tests and two by the vendor.

Change-Id: I46e2a5ea338eddacdfd089f696295dbd16795c5a
diff --git a/private/file_contexts b/private/file_contexts
index ef4f2c7..cf4c69b 100644
--- a/private/file_contexts
+++ b/private/file_contexts
@@ -360,6 +360,7 @@
 
 /vendor/apex(/[^/]+){0,2}                      u:object_r:vendor_apex_file:s0
 /vendor/bin/misc_writer                        u:object_r:vendor_misc_writer_exec:s0
+/vendor/bin/boringssl_self_test(32|64)         u:object_r:vendor_boringssl_self_test_exec:s0
 
 # HAL location
 /(vendor|system/vendor)/lib(64)?/hw            u:object_r:vendor_hal_file:s0