Support handling multidimensional arrays

[remeio]

Resolve TODO: TODO - only handles 2-dimensional arrays.

For method org.springframework.beans.AbstractNestablePropertyAccessor#newValue:

• When arg type is Integer[][][].class, it will return a 2-dimensional array instance like[[]].

After this PR, this method support handling multidimensional arrays:

• When arg type is Integer[][][].class, it will return a 3-dimensional array instance like [[[]]].

But actually, this final behavior is correct before this PR. For example:

• Test case org.springframework.beans.BeanWrapperAutoGrowingTests#getPropertyValueAutoGrow3dArray had passed.

So I just fix this method newValue.

[snicoll]

@remeio thanks for the PR but there are no tests that showcase what the code has changed. We can't consider the PR until you amend it with additional unit tests.

[remeio]

@snicoll Hi，I had add the test case for list of 3-dimensional array like List<Bean[][][]>.

I think the default 3-dimensional array should be [[[]]]. But it is [[]] before this PR.

You can see the test method: getPropertyValueAutoGrow3dArrayListForDefault3dArray

Look forward to your reply.