RFR: JDK-8223335: Compare baseline builds on linux are failing

[Erik Joelsson]

Since JDK-8221851, the COMPARE_BUILD baseline builds have started 
failing. This seems to be caused by the same issue as affected 
reconfigure when introducing that change. A call to configure from make 
requires a cd to CONFIGURE_START_DIR first.

Bug: https://bugs.openjdk.java.net/browse/JDK-8223335

Webrev: http://cr.openjdk.java.net/~erikj/8223335/webrev.01

/Erik