Gets the "zero" (or {@code null}) value for the given type.
switch (type.getBasicType()) {
case Type.BT_BOOLEAN: return CstBoolean.VALUE_FALSE;
case Type.BT_BYTE: return CstByte.VALUE_0;
case Type.BT_CHAR: return CstChar.VALUE_0;
case Type.BT_DOUBLE: return CstDouble.VALUE_0;
case Type.BT_FLOAT: return CstFloat.VALUE_0;
case Type.BT_INT: return CstInteger.VALUE_0;
case Type.BT_LONG: return CstLong.VALUE_0;
case Type.BT_SHORT: return CstShort.VALUE_0;
case Type.BT_OBJECT: return CstKnownNull.THE_ONE;
default: {
throw new UnsupportedOperationException("no zero for type: " +
type.toHuman());
}
}