init: compile out oom_score_adjust code on microdroid

Saves 1,436 bytes.

size -A out/soong/.intermediates/system/core/init/init_second_stage.microdroid/android_arm64_armv9-2a_cortex-a55/init

Bug: 416570070
Test: m
Flag: EXEMPT .
Change-Id: I5a337ca49d7337506af556f9d7a2a37a92ffffcc