[aarch64-port-dev ] RFC 8169201: Montgomery multiply intrinsic should use correct name

[Aleksey Shipilev]

We have recently pulled from aarch64-port/jdk8u to shenandoah/jdk8u, and got interesting bugs.

In Shenandoah code, we *do* care about stub names for analysis/verification. In upstream, there is a
fix for "Montgomery multiply intrinsic should use correct name", which is missing in current
aarch64-port/jdk8u:
  https://bugs.openjdk.java.net/browse/JDK-8169201

Per repo status:
 - aarch64-port/jdk8u DOES NOT have it
 - aarch64-port/sheandoah-jdk8u has it from our fixes
 - shenandoah/jdk8u has it from our fixes
 - shenandoah/jdk9 has it from upstream
 - shenandoah/jdk10 has it from upstream
 - shenandoah/jdk has it from upstream

This is a landmine during merges, because we can always accidentally reintroduce the bug. Maybe it
makes sense to pick up JDK-8169201 to aarch64-port/jdk8u?

Thanks,
-Aleksey