Convert dtrace probes to use operations

Convert dtrace probes to use operations

This changes dtrace to use the new operation type.

gdb/ChangeLog
2021-03-08  Tom Tromey  <tom@tromey.com>

	* gdbarch.sh (dtrace_parse_probe_argument): Change return type.
	* gdbarch.h: Rebuild.
	* gdbarch.c: Rebuild.
	* dtrace-probe.c (dtrace_probe::build_arg_exprs): Update.
	* amd64-linux-tdep.c (amd64_dtrace_parse_probe_argument): Change
	return type.
	(amd64_dtrace_parse_probe_argument): Update.