Use GNU style for metasyntactic variables in gdb

Use GNU style for metasyntactic variables in gdb

I searched for other spots that did not use the GNU style for
metasyntactic syntactic variables.  This patch fixes most of the ones
I found in gdb proper.  There are a few remaining in MI, but I was
unsure whether those should be touched.

gdb/ChangeLog
2018-09-16  Tom Tromey  <tom@tromey.com>

	* top.c (new_ui_command): Use GNU style for metasyntactic
	variables.
	* breakpoint.c (stopat_command): Use GNU style for metasyntactic
	variables.
	* maint.c (maintenance_translate_address): Remove "<>" around
	text.
	* interps.c (interpreter_exec_cmd): Use GNU style for
	metasyntactic variables.
	* nto-procfs.c (nto_procfs_target_info): Use GNU style for
	metasyntactic variables.
	* tracepoint.c (tfind_range_command): Use GNU style for
	metasyntactic variables.
	(tfind_outside_command): Likewise.
	(_initialize_tracepoint): Likewise.
	* remote.c (extended_remote_target::create_inferior): Use GNU
	style for metasyntactic variables.
	* sparc64-tdep.c (adi_examine_command): Use GNU style for
	metasyntactic variables.
	(adi_assign_command): Likewise.

gdb/testsuite/ChangeLog
2018-09-16  Tom Tromey  <tom@tromey.com>

	* gdb.base/new-ui.exp (do_execution_tests): Update.
	* gdb.base/dbx.exp (test_breakpoints): Update.