[8u-dev] RFA: 8206075: On x86, assert on unbound assembler Labels used as branch targets

[Hohensee, Paul]

Please approve this small backport to jdk8u. The original patch had a bug that was fixed by
8208480: Fix for test failure: assert(is_bound() || is_unused()) after JDK-8206075 in C1
for which a backport request immediately follows this one.
JBS: https://bugs.openjdk.java.net/browse/JDK-8206075
Webrev: http://cr.openjdk.java.net/~phh/8206075/webrev.8u.00/
Review thread: http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2018-July/029136.html

The patch applies cleanly net of line number changes and file locations.

Webrev combined with 8208480: http://cr.openjdk.java.net/~phh/8206075/webrev.8u.8208480.combined/

Thanks,

Paul