hg: build-infra/jdk9: Bug fix for icecc: run cd in sub shell to avoid 'sed: can't read confdefs.h'

[magnus.ihse.bursie at oracle.com]

Changeset: 3c2ad314a0e0
Author:    ihse
Date:      2016-02-09 21:57 +0100
URL:       http://hg.openjdk.java.net/build-infra/jdk9/rev/3c2ad314a0e0

Bug fix for icecc: run cd in sub shell to avoid 'sed: can't read confdefs.h'

! common/autoconf/build-performance.m4
! common/autoconf/generated-configure.sh