hg: graal/graal-jvmci-8: Backport isImmutablePIC field from jvmci-9, and add documentation.

[doug.simon at oracle.com]

Changeset: 5d06abd6d35b
Author:    Roland Schatz <roland.schatz at oracle.com>
Date:      2016-01-20 11:13 +0100
URL:       http://hg.openjdk.java.net/graal/graal-jvmci-8/rev/5d06abd6d35b

Backport isImmutablePIC field from jvmci-9, and add documentation.

! jvmci/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotCompiledCode.java
! jvmci/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotCompiledNmethod.java