[8u] RFR: 8207057: No debug info for assembler files

[Severin Gehwolf]

Hi,

Please review this 8u backport of JDK-8207057 which adds debug info
when assembling assembler files. The build system changed between 9+
and 8u, so it's an independent patch from JDK 12's version.

Bug: https://bugs.openjdk.java.net/browse/JDK-8207057
webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8207057/jdk8/01/

Testing: Debugging of assembler files in gdb. Eyeballing compile logs.

Thoughts?

Thanks,
Severin