Revert change making jdt compiler use project settings

[akurtakov]

Should fix
eclipse-platform/eclipse.platform.releng.aggregator#1653 .
Further work on the topic could be continued as described in #973 (comment)

[akurtakov]

Push without waiting as comparator issues shouldn't break the verification build and start I-build to get results ASAP.

[jukzi]

Since the comparator issue was analysed anderstood can this revert be reverted and comparator get a reset?

[akurtakov]

@srikanth-sankaran @iloveeclipse WDYT ? Should we go for preserveLocal and touch all needed bundles?

If that's the path recomended by compiler guys the change should happen in https://github.com/eclipse-platform/eclipse.platform.releng.aggregator/blob/3e6518b64e478f6f31375307c185eaf15706d9e6/eclipse-platform-parent/pom.xml#L485 and not be a revert of this one.

[iloveeclipse]

Alex, I'm for a buuild that uses (consistent) project settings accross all projects in aggregator.
Ideally what project defines in settings should be used in all project builds - IDE, Jenkins, SDK aggregator build.
If that line in parent pom makes it - perfect.
We should check before if all the various Jenkins files and poms don't override that again with something different. And ideally we should check if all the projects have compiler settings at all.
Unfortunately I can't commit to drive that, as I'm busy with other tasks.