[8u] RFR 8235687: Contents/MacOS/libjli.dylib cannot be a symlink

[Dmitry Cherepanov]

JBS: https://bugs.openjdk.java.net/browse/JDK-8235687
original review: 
https://mail.openjdk.java.net/pipermail/build-dev/2019-December/026452.html
patch for 11u: 
https://hg.openjdk.java.net/jdk-updates/jdk11u-dev/rev/1859de77ee6c

webrev for 8u: 
http://cr.openjdk.java.net/~dcherepanov/openjdk8u/8235687/webrev.v0/

The patch doesn’t apply cleanly due to the lack of SetupCopyFiles which 
was added with the transition to the modular system 8054834. The patch 
directly calls the cp utility, this is consistent with how the images 
are copied a few lines above. The second part of the patch (phony target 
with recipes modifying files) also does not apply as is. This is an 
optional refactoring, and for simplicity, this part has been omitted.

This fix also requires a follow-up fix (8238225), a review request for 
which will be sent separately.

Thanks,

Dmitry