code review 5868048: test: use testlib in a few more cases

test/method4a.go

-// true
+// skip
 
 // Copyright 2012 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // Test method expressions with arguments.
 // This file is not tested by itself; it is imported by method4.go.
 
 package method4a
 
@@ skipping 19 matching lines @@
         return r
 }
 
 func (p *T2) Sum(a []int, b int) int {
         r := p.F + b
         for _, v := range a {
                 r += v
         }
         return r
 }