RFR: 2018-03-19, Bulk backports to sh/jdk10

[Aleksey Shipilev]

http://cr.openjdk.java.net/~shade/shenandoah/backports/jdk10-20180319/webrev.01/

This backports last week's work to sh/jdk10:

1c743cca5468: [backport] Revert EA difference against upstream
5789a22b66bd: [backport] Fix || and && chaining warnings in memnode.cpp
2742d73decc4: [backport] Use jint in oom-evac-handler to match older JDKs Atomic support better
79d0e462ff4a: [backport] Missing OOMScope in ShenandoahFixRootsTask
d82146d195fc: [backport] Remove ConstantOopWriteValue::write_on workaround in favor of upstream fix
285698964c3a: [backport] fix PhaseIdealLoop::place_near_use() with loop strip mining
a248f5651744: [backport] fix for alias analysis with ShenandoahBarriersForConst
dcc1ef08dc0e: [backport] FinalEvac pause to turn off evacuation
4366aab742d0: [backport] Little cleanup
7edfd55938a2: [backport] Tax-and-Spend allocation pacing

Testing: hotspot_gc_shenandoah {fastdebug|release}

Thanks,
-Aleksey