[Refactor] generalize error message from calling .end more than once

Author: ljharb

lib/test.js

@@ -151,7 +151,7 @@ Test.prototype.end = function (err) {
     }
 
     if (this.calledEnd) {
-        this.fail('.end() called twice');
+        this.fail('.end() already called');
     }
     this.calledEnd = true;
     this._end();

test/double_end.js

@@ -39,12 +39,12 @@ test(function (t) {
             'TAP version 13',
             '# double end',
             'ok 1 should be equal',
-            'not ok 2 .end() called twice',
+            'not ok 2 .end() already called',
             '  ---',
             '    operator: fail',
             '    ' + atExpected,
             '    stack: |-',
-            '      Error: .end() called twice',
+            '      Error: .end() already called',
             '          [... stack stripped ...]',
             '          ' + stackExpected,
             '          [... stack stripped ...]',