[Java] Fix overflow issue when requesting large buffer size.

[epickrram]

Fixes an infinite loop when calculated newCapacity overflows:

final int newCapacity = Math.max(capacity + (capacity >> 1), MIN_ALLOCATED_CAPACITY);
// newCapacity is never negative, as Math.max returns MIN_ALLOCATED_CAPACITY
// when capacity + (capacity >> 1) overflows
if (newCapacity < 0 || newCapacity > MAX_CAPACITY)

Extracted utility method out to separate class to facilitate testing.