[testsuite] add gdb.cp/gdb1355.exp

[Michael Elizabeth Chastain]

dc> For one thing, it would be an XFAIL, because it's a GCC bug,
dc> not a GDB bug.

The test script, gdb.cp/gdb1355.exp, refers to PR gdb/1355.
gdb/1355 is an external PR and it refers to PR gcc/12066.
So there is a gdb PR in there.

dc> For another thing, though, the bug in question has been fixed,
dc> so we don't expect it to fail: if it does, it should show up as a FAIL.

This has been a controversy in the past, too.

My view is that "KFAIL" means "Known FAIL", which basically means
there is a PR for it (the PR is the locus of knowledge).

dc> I would leave in the new test, with branches and comments as is,
dc> but I would change all the occurrences of kfail to fail.

I prefer gdb1355.exp the way it is but I would be okay with that change
if other people want it that way.

Michael C