liblog: __android_log_error_write in vndk

Also added log_safetynet.h header. This contains a memory sensitive logging
function which is used to detect attack attempts.

Fixes: 37442967
Test: liblog-unit-tests on internal marlin
Test: build liblog with BOARD_VNDK_VERSION := current on aosp_arm
Test: libbinder vendor variant links with BOARD_VNDK_VERSION := current

Change-Id: Icfcc2b1acbb3712bf4c84403870dc93401eafb15