Inlcude absi in MathToVM Pattern and add testcases for it (#24592)

We have found some models, which failed to compile to vmvx, due to a
missing conversion for math.absi.

#7080 already implemented vm.abs.i32 and vm.abs.i64 and included a
GenericOpConversion in
[VMToEmitC/ConvertVMToEmitC.cpp](https://github.com/iree-org/iree/blob/a9e91ecb68b23241349acfbb2ede00afa4c107b7/compiler/src/iree/compiler/Dialect/VM/Conversion/VMToEmitC/ConvertVMToEmitC.cpp#L5037-L5038)

It only requies a simple addition to the patterns in
MathToVM/Patterns.cpp, for the models to successfully compile to vmvx. I
also expanded the tests in arithmetic_ops.mlir, to include a check for
vm.abs.i32 and vm.abs.i64.

Signed-off-by: Hakan Eyilmez <eyilmez@roofline.ai>

Signed-off-by: default <eyilmez@roofline.ai>