Disable file compaction by default

At present time kernel does not support shared pages to be
swapped using file compaction which uses MADV_COLD and most
of the file pages in a process are actually shared mappings
causing us to waste a lot of cycles scanning through a lot
of unreclaimable pages, this patch disables file compaction
which will be reenabled until a solution is implemented on
upstream kernel that allows reclaiming shared pages, thus
making it worth to scan all of those pages again.

Test: am compact file <processname> <uid>
Bug: 265473345
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:30b069612a9d35b02cc6c2656c18326e8cffeec6)
Merged-In: I4c819058da229c00d1eafea636f89784718adc5f
Change-Id: I4c819058da229c00d1eafea636f89784718adc5f