[8u] RFR (S) 8079891: Store configure log in $BUILD/configure.log

[Aleksey Shipilev]

Original RFE:
   https://bugs.openjdk.java.net/browse/JDK-8079891
   https://hg.openjdk.java.net/jdk9/jdk9/rev/98e85b507b09

I would like to have this simple build feature in 8u to better report configuration logs from 8u 
CIs. This patch applies mostly trivially, with the following changes:
   *) Blocks mentioning CONFIGURESUPPORT_OUTPUTDIR are removed, as these are not relevant to 8u 
build system;
   *) Minor contextual conflicts are resolved;

Current patch needs JDK-8065215 applied first to get the help block at the end of configure. This 
also needs JDK-8080082 as the follow-up.

Testing: 8u build; observing configure.log in build artifacts

-- 
Thanks,
-Aleksey