StringUtils.chompLast throws StringIndexOutOfBoundsException when sep is longer than str

StringUtils.chompLast(@NonNull String str, @NonNull String sep) (line 853) computes str.substring(str.length() - sep.length()) at line 857. If sep is longer than str, the start index is negative, causing StringIndexOutOfBoundsException.

For example: chompLast("x", "ab") throws.

Fix: add a guard returning str when sep.length() > str.length().