[mlir][NFC] Remove redundant insertion point changes (#161837)

These insertion points were added in
llvm/llvm-project#146551 and
llvm/llvm-project#146908 to support the one-shot
dialect conversion driver which performs changes to the IR immediately
and would otherwise invalidate previous insertion points.

Since then, the insertion point has been made resilient against op
erasure (llvm/llvm-project#146955) making the
changes now redundant.

Author: zero9178

mlir/lib/Conversion/SPIRVToLLVM/ConvertLaunchFuncToLLVMCalls.cpp

@@ -267,9 +267,8 @@ class GPULaunchLowering : public ConvertOpToLLVMPattern<gpu::LaunchFuncOp> {
       copyInfo.push_back(info);
     }
     // Create a call to the kernel and copy the data back.
-    Operation *callOp = rewriter.replaceOpWithNewOp<LLVM::CallOp>(
-        op, kernelFunc, ArrayRef<Value>());
-    rewriter.setInsertionPointAfter(callOp);
+    rewriter.replaceOpWithNewOp<LLVM::CallOp>(op, kernelFunc,
+                                              ArrayRef<Value>());
     for (CopyInfo info : copyInfo)
       copy(loc, info.src, info.dst, info.size, rewriter);
     return success();

mlir/lib/Conversion/TosaToLinalg/TosaToLinalgNamed.cpp

@@ -802,7 +802,6 @@ class MaxPool2dConverter : public OpConversionPattern<tosa::MaxPool2dOp> {
         ValueRange{paddedInput, fakeWindowDims}, filledEmptyTensor, strideAttr,
         dilationAttr);
 
-    rewriter.setInsertionPointAfter(op);
     NanPropagationMode nanMode = op.getNanMode();
     rewriter.replaceOp(op, resultOp);