Revert "parser: cache tokens (first step)"

This reverts commit 8992707fbb.

compiler/scanner.v

@@ -785,6 +785,26 @@ fn (s mut Scanner) ident_char() string {
 	return if c == '\'' { '\\' + c } else { c }
 }
 
+fn (s mut Scanner) peek() Token {
+	// save scanner state
+	pos := s.pos
+	line := s.line_nr
+	inside_string := s.inside_string
+	inter_start := s.inter_start
+	inter_end := s.inter_end
+
+	res := s.scan()
+	tok := res.tok
+
+	// restore scanner state
+	s.pos = pos
+	s.line_nr = line
+	s.inside_string = inside_string
+	s.inter_start = inter_start
+	s.inter_end = inter_end
+	return tok
+}
+
 fn (s &Scanner) expect(want string, start_pos int) bool {
 	end_pos := start_pos + want.len
 	if start_pos < 0 || start_pos >= s.text.len {