cgen: fix comptime if expr T.typ is type (fix #13118)

[yuyi98]

This PR fix comptime if expr T.typ is type (fix #13118).

• Fix comptime if expr T.typ is type.
• Add test.

module main

fn write<T>(out T) string {
	$if T.typ is bool {
		println('FOO')
		return 'FOO'
	} $else $if T.typ !is bool {
		println('BAR')
		return 'BAR'
	}
	return 'EMPTY'
}

fn main() {
	mut val := false
	ret := write<bool>(val)
	assert ret == 'FOO'
}

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