[TVMScript] Sugar Var Definition in TIR Buffer

[junrushao]

This PR introduces sugars for TIR buffer declaration.

Sugar 1. Convenient stride definition by string.

// Previous
stride = T.int32()
A = T.match_buffer(..., strides=(stride,))

// This PR
A = T.match_buffer(..., strides=("s0", ))

Sugar 2. Multiple definition of TIR Var from a single buffer are now merged into a single line.

// Previous
m = T.int32()
n = T.int32()
stride = T.int32()
stride_1 = T.int32()
A = T.match_buffer(a, (m, n), strides=(stride, stride_1))

// This PR
m, n = T.int32(), T.int32()
A = T.match_buffer(a, (m, n), strides=("s0", "s1"))

[tvm-bot]

Thanks for contributing to TVM! Please refer to the contributing guidelines https://tvm.apache.org/docs/contribute/ for useful information and tips. Please request code reviews from Reviewers by @-ing them in a comment.

• cc @Hzfengsy, @shingjan _{See #10317 for details}

_{Generated by tvm-bot}

[tqchen]

LGTM