[mlir][bufferization] Use rewriter to erase ops in scf.forall bufferization.

[ThomasRaoux]

Summary

Without this bufferization cannot track operations removed during bufferization.
Unfortunately there is currently no way to enforce that ops need to be erased through
the rewriter and this causes sporadic errors when tracking pointers in Bufferization pass.
Therefore there is no easy way to test that the pattern is doing the right thing.

mlir/lib/Dialect/SCF/Transforms/BufferizableOpInterfaceImpl.cpp

LogicalResult bufferize(Operation *op, RewriterBase &rewriter,
     // introduced terminator.
     rewriter.setInsertionPoint(forallOp);
     ForallOp newForallOp;
     newForallOp = rewriter.create<ForallOp>(
         forallOp.getLoc(), forallOp.getMixedLowerBound(),
         forallOp.getMixedUpperBound(), forallOp.getMixedStep(),
         /*outputs=*/ValueRange(), forallOp.getMapping());
 
-    newForallOp.getBody()->getTerminator()->erase();
+    rewriter.eraseOp(newForallOp.getBody()->getTerminator());
 
     // Move over block contents of the old op.
     SmallVector<Value> replacementBbArgs;
     replacementBbArgs.append(newForallOp.getBody()->getArguments().begin(),
                              newForallOp.getBody()->getArguments().end());
     replacementBbArgs.append(forallOp.getOutputs().size(), Value());
     rewriter.mergeBlocks(forallOp.getBody(), newForallOp.getBody(),
                          replacementBbArgs);