Attempt to fix tests on Windows

Author: ljharb

test/resolver.js

@@ -309,7 +309,7 @@ test('async: #121 - treating an existing file as a dir when no basedir', functio
     t.test('with a trailing slash', function (st) {
         st.plan(4);
 
-        resolve('./' + testFile + '/', function (err, res, pkg) {
+        resolve('./' + testFile + path.sep, function (err, res, pkg) {
             st.ok(err, 'there is an error');
             st.notOk(res, 'no result');
 

test/resolver_sync.js

@@ -231,7 +231,7 @@ test('sync: #121 - treating an existing file as a dir when no basedir', function
     });
 
     t.test('with a trailing slash', function (st) {
-        function run() { return resolve.sync('./' + testFile + '/'); }
+        function run() { return resolve.sync('./' + testFile + path.sep); }
 
         st.throws(run, 'throws an error');