aoqi@0: 'abc'.lastIndexOf('a', 4) = 0
aoqi@0: 'abc'.lastIndexOf('b', Infinity) = 1
aoqi@0: 'abc'.lastIndexOf('a', -1) = 0
aoqi@0: 'abc'.lastIndexOf('a', -Infinity) = 0
aoqi@0: 'oracle'.lastIndexOf('u') = -1
aoqi@0: 'hello'.lastIndexOf('l') = 3
aoqi@0: 'hello'.lastIndexOf('l', 2) = 2
aoqi@0: 'hello'.lastIndexOf('l', 3) = 3
aoqi@0: 'hello'.lastIndexOf('l', 1) = -1