RFR: JDK-8146533: javac: No line numbers in compilation error

[Srikanth]

Hello !

Please review the fix for https://bugs.openjdk.java.net/browse/JDK-8146533
made available at 
http://cr.openjdk.java.net/~sadayapalam/JDK-8146533/webrev.00/

This is basically an 8u76 candidate backport of an identical fix made 
for JDK9
via https://bugs.openjdk.java.net/browse/JDK-8145466

Reason for the review request being, the patch from JDK 9 does not 
mechanically
apply as is after path shuffling. However, manual application does not 
call for any
new changes.

All relevant tests are grreen.

Thanks!
Srikanth.