[Backend] Improve dot support to target FMA

[binarman]

This PR:

• Refactors FMA dot implementation
• Supports dot3d in FMA path
• Fixes several issues in operand offset computation
• Enables small dot operands

This PR is a part of PR series. Final goal is to improve efficiency of small dot operations and bypass as much shared memory accesses as possible.

Rough list of PRs:

• [ ] Basic FMA dot fixes, dot 3d support and relaxing small dimensions for dot (this PR) #4516
• [ ] Blocked->dotOp shared memory bypassing #4538
• [ ] Accelerate AMD Matmul + emit dot operations #4594
• [ ] Layout optimization, so operand B is loaded in proper mfma layout and do not need to go through LDS #4581
• [ ] Vectorization optimization of dot operands/results (in case llvm can not do this internally)
• [ ] Reduction operation hoisting out of the K loop (reduction operation is a byproduct of layout optimization step) #4559