Multi-dimensional array helpers

When allocating a multi-dimensional array we create an int array with one element per dimension of the array. This array becomes redundant after the array is allocated but the array allocation is never removed by escape analysis. Whilst we can't pass a variable number of arguments there are or could be cases where we should have a specific allocation route. Commits 14083-14085 introduce such a helper for 2 dimensional arrays, which looking through DaCapo and Classpath's source code were found to be the most abundant. Further helpers could be introduced for other multi dimensional array "dimensionalities", avoiding the need to allocate the int array.