Reword some btrace error messages to align with the format discussed in https://sourceware.org/ml/gdb-patches/2018-02/msg00135.html. gdb/ * remote.c (remote_btrace_maybe_reopen): Change error message. * btrace.c (btrace_enable): Likewise. (parse_xml_btrace): Likewise. (parse_xml_btrace_conf): Likewise. testsuite/ * lib/gdb.exp (skip_btrace_pt_tests): Update expected error message. Fix test name.