Multidimensional array can not be reconstructed if memory accesses are done at another statements

[ptomin]

See following unit test:

reko/src/UnitTests/Decompiler/Typing/TypedExpressionRewriterTests.cs

Line 1703 in 7e783de

                 m.MStore(m.IAdd(r0, m.IAdd(m.IMul(r2, 8), 4)), m.Word32(2)); 

Expected: a + r1
But was: a + r1 * 0x20