Switch member calls to isa/dyn_cast/cast/... to free function calls. (#89356)

This change cleans up call sites. Next step is to mark the member
functions deprecated.

See https://mlir.llvm.org/deprecation and
https://discourse.llvm.org/t/preferred-casting-style-going-forward.

mlir/lib/Dialect/SparseTensor/Transforms/SparseTensorRewriting.cpp

@@ -476,8 +476,8 @@ private:
     if (!sel)
       return std::nullopt;
 
-    auto tVal = sel.getTrueValue().dyn_cast<BlockArgument>();
-    auto fVal = sel.getFalseValue().dyn_cast<BlockArgument>();
+    auto tVal = dyn_cast<BlockArgument>(sel.getTrueValue());
+    auto fVal = dyn_cast<BlockArgument>(sel.getFalseValue());
     // TODO: For simplicity, we only handle cases where both true/false value
     // are directly loaded the input tensor. We can probably admit more cases
     // in theory.
@@ -487,7 +487,7 @@ private:
     // Helper lambda to determine whether the value is loaded from a dense input
     // or is a loop invariant.
     auto isValFromDenseInputOrInvariant = [&op](Value v) -> bool {
-      if (auto bArg = v.dyn_cast<BlockArgument>();
+      if (auto bArg = dyn_cast<BlockArgument>(v);
           bArg && !isSparseTensor(op.getDpsInputOperand(bArg.getArgNumber())))
         return true;
       // If the value is defined outside the loop, it is a loop invariant.