[8u] RFA: 8207402: Stray *.debuginfo files when not stripping debug info

[Severin Gehwolf]

Hi,

Please approve this 8u-only build fix relating to debug info generation
of hotspot libraries. For builds where no debuginfo stripping should be
happening, *.debuginfo files get currently created anyway.

Bug: https://bugs.openjdk.java.net/browse/JDK-8207402
webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8207402/webrev.01/
review-thread: http://mail.openjdk.java.net/pipermail/build-dev/2018-July/022691.html

Thanks,
Severin