Add SysProp to set the number of threads for opening apex file

Test: manually boot and verify the thread count in log

Bug: 399312005
Ignore-AOSP-First: AOSP merge process change
Change-Id: I39f77229342b587cb90ad2ee3abfb6e71839ce8f
diff --git a/private/property_contexts b/private/property_contexts
index 7910919..39a852f 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -332,6 +332,7 @@
 
 apexd.                  u:object_r:apexd_prop:s0
 apexd.config.           u:object_r:apexd_config_prop:s0
+apexd.config.apex_file_open.threads      u:object_r:apexd_config_prop:s0 exact uint
 apexd.config.dm_delete.timeout           u:object_r:apexd_config_prop:s0 exact uint
 apexd.config.dm_create.timeout           u:object_r:apexd_config_prop:s0 exact uint
 apexd.config.loop_wait.attempts          u:object_r:apexd_config_prop:s0 exact uint