Revert "Enable lowmemorykiler trace event toggling."

Reverting this commit to fix CTS tests in oc-dr.
This reverts commit 718e0852.

Test: Tested lowmemorykiller tracing removed via traceur.
Bug: 62908858
Merged-In: Ifc1c6ac634b94e060ed1f311049bd37f6fcc8313

Change-Id: Ie462decf32578bbe74a9ec9bdb8bb4ae1b87da29

private/file_contexts

@@ -490,7 +490,6 @@
 /sys/kernel(/debug)?/tracing/events/vmscan/mm_vmscan_direct_reclaim_end/enable      u:object_r:tracing_shell_writable:s0
 /sys/kernel(/debug)?/tracing/events/vmscan/mm_vmscan_kswapd_sleep/enable            u:object_r:tracing_shell_writable:s0
 /sys/kernel(/debug)?/tracing/events/vmscan/mm_vmscan_kswapd_wake/enable             u:object_r:tracing_shell_writable:s0
-/sys/kernel(/debug)?/tracing/events/lowmemorykiller/enable                          u:object_r:tracing_shell_writable:s0
 /sys/kernel(/debug)?/tracing/instances(/.*)?                                        u:object_r:debugfs_tracing_instances:s0
 /sys/kernel(/debug)?/tracing/instances/wifi/free_buffer                             u:object_r:debugfs_wifi_tracing:s0
 /sys/kernel(/debug)?/tracing/instances/wifi/trace                                   u:object_r:debugfs_wifi_tracing:s0