[mlir][arith] arith-to-apfloat: Add vector support (#171024)

Add support for vectorized operations such as `arith.addf ... :
vector<4xf4E2M1FN>`. The computation is scalarized: scalar operands are
extracted with `vector.to_elements`, multiple scalar computations are
performed and the result is inserted back into a vector with
`vector.from_elements`.

Author: matthias-springer

mlir/include/mlir/Conversion/Passes.td

@@ -198,7 +198,8 @@ def ArithToAPFloatConversionPass
     calls (APFloatWrappers.cpp). APFloat is a software implementation of
     floating-point arithmetic operations.
   }];
-  let dependentDialects = ["func::FuncDialect"];
+  let dependentDialects = ["arith::ArithDialect", "func::FuncDialect",
+                           "vector::VectorDialect"];
 }
 
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