test: fix test-require-resolve.js on iOS.

In iOS the test folder is copied to a temp folder with write access,
therefore 'common.fixturesDir' starts from a different root compared
to '__dirname'.

test/simple/test-require-resolve.js

@@ -10,8 +10,13 @@ assert.equal(path.join(__dirname, '../fixtures/a.js'),
              require.resolve('../fixtures/a'));
 assert.equal(path.join(fixturesDir, 'a.js'),
              require.resolve(path.join(fixturesDir, 'a')));
-assert.equal(path.join(fixturesDir, 'nested-index', 'one', 'index.js'),
-             require.resolve('../fixtures/nested-index/one'));
+if (process.platform === 'ios') {
+  assert.equal(path.join(__dirname, '../fixtures', 'nested-index', 'one', 'index.js'),
+               require.resolve('../fixtures/nested-index/one'));
+} else {
+  assert.equal(path.join(fixturesDir, 'nested-index', 'one', 'index.js'),
+               require.resolve('../fixtures/nested-index/one'));
+}
 assert.equal('path', require.resolve('path'));
 
-console.log('ok');
+console.log('ok');