[TIR] Fix RenewDef for symbolic input shapes

[junrushao]

There are cases where the shapes of input buffers are symbolic, but the first symbol is a composite PrimExpr rather than a TIR Var, which the original implementation does not take this into account.

Example:

@T.prim_func
def main(a: T.handle, b: T.handle):
    m = T.int64()
    A = T.match_buffer(a, (m * 2,))  // `m` first appears as composite
    B = T.match_buffer(b, (m, 2))

[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, @quic-sanirudh, @shingjan _{See #10317 for details}

_{Generated by tvm-bot}