test-fs-realpath is broken on iOS

[enricogior]

There are two places where test/simple/test-fs-realpath.js doesn't work on iOS:

• https://github.com/thaliproject/jxcore/blob/master/test/simple/test-fs-realpath.js#L257
• https://github.com/thaliproject/jxcore/blob/master/test/simple/test-fs-realpath.js#L349

The fix consists in changing line 257:

var entry = common.tmpDir.substr(entrydir.length + 1) + '/cycles/realpath-3a';

to:

  var entry;
  if (entrydir.charAt(0) === '.') {
    entry = common.tmpDir.substr(entrydir.length + 1);
  } else {
    entry = common.tmpDir;
  }
  entry += '/cycles/realpath-3a';

Same type of fix for line 349:

  var entry;
  if (entrydir.charAt(0) === '.') {
    entry = tmpAbsDir.substr(entrydir.length + 1);
  } else {
    entry = tmpAbsDir;
  }
  entry += '/cycles/root.js';