[PATCH] GDB Testsuite, update compile-cplus.exp

[PATCH] GDB Testsuite, update compile-cplus.exp

[PATCH] GDB Testsuite, update compile-cplus.exp

Update the gdb.compile/compile-cplus.exp test to
handle errors generated when passing bad arguments
into the gdb-compile command.
This matches changes made to gdb.compile/compile.exp
in the past as part of
"Migrate rest of compile commands to new options framework"
         e6ed716cd5514c08b9d7c469d185b1aa177dbc22