ANDROID: mm, oom: add vendor hook to prevent oom panic

In some cases we would like to bypass oom panic and give the system more
time to cleanup memory. Add vendor hook to allow skipping the oom panic.

Bug: 186875166
Change-Id: I64e74b2c013d6f18d74504777c6559d9ae07e008
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>