Change: non-compliant deprecated String methods were removed.

Change: non-compliant deprecated String methods were removed.

The following methods were removed:
    String.bytesFrom(),
    String.prototype.fromBytes(),
    String.prototype.fromUTF8(),
    String.prototype.toBytes(),
    String.prototype.toUTF8(),
    String.prototype.toString(encoding).

Because String.bytesFrom() was used to test the existing code
which works with byte strings it was replaced with $262.bytesString()
which is only available in unit tests.