logd: sock_alloc_send_pskb starves pruning

(cherry pick from commit 5c77ad55)

Allow socket send syscall to terminate after 32 seconds if reader
stalled because of memory pressure allocating new network buffers

Add a gTest to catch regressions, add security buffer to log_dump

Bug: 27242723
Change-Id: Idaa6699d9d284e7f5f723ae0e76b3d6aa3371489