[mlir][Linalg] Implement fusion of linalg.generic operation on tensors.

[mlir][Linalg] Implement fusion of linalg.generic operation on tensors.

The initial implementation of the fusion operation exposes a method to
fuse a consumer with its producer, when
- both the producer and consumer operate on tensors
- the producer has only a single result value
- the producer has only "parallel" iterator types
A new interface method hasTensorSemantics is added to verify that an
operation has all operands and results of type RankedTensorType.

Differential Revision: https://reviews.llvm.org/D74172