[8] RFA 8033251: Use DWARF debug symbols for Linux 32-bit as default

[David Buck]

Hi!

Please approve the backport of this build file change. This change is 
needed to support building with modern toolchains on Linux.

bug report:
https://bugs.openjdk.java.net/browse/JDK-8033251

backport review thread:
http://mail.openjdk.java.net/pipermail/build-dev/2018-August/022874.html

webrev:
see review thread above

enhancement request / approval:
http://mail.openjdk.java.net/pipermail/jdk8u-dev/2018-March/007321.html

JPRT build/test run and passed with current toolchains on all 
Oracle-supported platforms.

Cheers,
-Buck