[8u40] Request for Approval: Backport of c1_LinearScan.cpp parfait changeset

[Morris Meyer]

Folks,

This is a backport of a parfait fix (8040921) to c1_LinearScan that 
should be backported from JDK9 to JDK 8u40.

The patch integrated cleanly and has been tested with JPRT.

The patches is made against:
http://hg.openjdk.java.net/jdk8u/hs-dev/hotspot

Thanks!

         --morris meyer

JBS - https://bugs.openjdk.java.net/browse/JDK-8054370
WEBREV - http://cr.openjdk.java.net/~morris/JDK-8054370.01