code review 5694082: go/printer: fix test for new import path restrictions

src/pkg/go/printer/testdata/declarations.golden

 // Copyright 2009 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.
 
 package imports
 
 import "io"
 
 import (
         _ "io"
@@ skipping 65 matching lines @@
         "io"
         "malloc"        // for the malloc count test only
         "math"
         "strings"
         "testing"
 )
 
 // more import examples
 import (
         "xxx"
-        "much longer name"      // comment
-        "short name"            // comment
+        "much_longer_name"      // comment
+        "short_name"            // comment
 )
 
 import (
         _ "xxx"
-        "much longer name"      // comment
+        "much_longer_name"      // comment
 )
 
 import (
         mymath "math"
         "/foo/bar/long_package_path"    // a comment
 )
 
 import (
         "package_a"     // comment
         "package_b"
@@ skipping 737 matching lines @@
                 w float,
                 x ...int)
 
         MultiLineSignature5(
                 a, b, c int,
                 u, v, w float,
                 p, q,
                 r string,
                 x ...int)
 }