[8u] RFR (XS) 8269953: config.log is not in build directory after 8u backport of JDK-8079891

[Aleksey Shipilev]

Apologies, I just introduced a minor 8u-specific build infra bug:
   https://bugs.openjdk.java.net/browse/JDK-8269953

Configure current jdk8u-dev and see:

jdk8u-dev $ find | grep config.log
config.log

...while it should be here:

jdk8u-dev $ find | grep config.log
./build/linux-x86_64-normal-server-fastdebug/config.log

This block was accidentally dropped:
   http://hg.openjdk.java.net/jdk8u/jdk8u-dev/rev/7cf12efdd88d#l3.11

8u webrev:
  http://cr.openjdk.java.net/~shade/8269953/webrev.8u.01/

Testing: observing where is config.log

-- 
Thanks,
-Aleksey