Configurations/10-main.conf: remove solaris-x86-cc target.

Since vendor assembler can't assemble our modules with -KPIC flag,
it, assembly support, was not available as an option. But this
means lack of side-channel resistant code, which is incompatible
with security by todays standards.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(cherry picked from commit 216a0cc4)