flag: fix parse_bool_value() with different order short args (fix #22176)

[yuyi98]

This PR fix parse_bool_value() with different order short args (fix #22176).

• Fix parse_bool_value() with different order short args.
• Add test.

import flag

fn main() {
	mut fp := flag.new_flag_parser(['-ba', '-c'])
	a_bool := fp.bool('a_bool', `a`, false, '')
	assert a_bool
	b_bool := fp.bool('b_bool', `b`, false, '')
	assert b_bool
	c_bool := fp.bool('c_bool', `c`, false, '')
	assert c_bool
	additional_args := fp.finalize()!
	println(additional_args.join_lines())
	assert additional_args == []
}

PS D:\Test\v\tt1> v run .