RFR: Sync up Shenandoah LSM handling with upstream

[Aleksey Shipilev]

http://cr.openjdk.java.net/~shade/shenandoah/lsm-args/webrev.01/

This fixes TestLoopMiningArguments.java failure, and does the same CLS/LSM handling like upstream
G1, and (hopefully) ZGC too [1]

Testing: hotspot_fast_gc_shenandoah, failing test

Thanks,
-Aleksey

[1] http://mail.openjdk.java.net/pipermail/zgc-dev/2017-December/000056.html