Add amm experiment.

See go/pixel-perf-amm-experiment for more info.

Bug: 365855872
Test: build/flash; set .Perf__amm_experiment=true, observe auto_migration_margins_enable value changing 1->0; set .Perf__amm_experiment="", observe the value changing 0->1
Flag: NONE controlled by Mendel instead
Change-Id: I02b98e3601a0564929acb73250e2e943664bc80a
Signed-off-by: Dmitry Skiba <dskiba@google.com>
4 files changed