Added gdb-remote test for software breakpoints.

Tests $Z0 and $z0.  Extends test exe get-code-address-hex:
to take a function name.

Enabled for debugserver, disabled for llgs.  Implementing
in llgs branch next.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@210272 91177308-0d34-0410-b5e6-96231b3b80d8