Remove fallback to /proc/pid/reclaim during app compaction

The /proc/pid/reclaim interface existed only on some device kernels, and
only until 4.19 which is now end of life (Dec. 2024). This UAPI was never upstream.

Bug: 374811051
Flag: EXEMPT cleanup
Change-Id: Ic7058c57d9ed25c3a100431dc5f9946dfa5b14ee