Spring Support handling multidimensional arrays

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.

Comment From: 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.

Comment From: 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.