previousClearBit
Returns the biggest index of a bit which value is
false
before
startIndex
(inclusive).
Returns -1 if there is no such bits before
startIndex
or if
startIndex
== -1.
If
startIndex
>= size will return
startIndex
assuming that the set has an infinite
sequence of
false
bits after (size - 1)-th.
Exceptions
IndexOutOfBoundException
- if
startIndex
< -1.