[Hexagon] 2-Stage Pipeline; Lower Async TIR primitives to Hexagon User DMA

[adstraw]

Creates a 2-stage pipeline (DMA, compute) by lowering Async TIR primitives (see RFC) with memory copy semantics to builtin functions for DMA Copy and Wait. These builtins can then be lowered through the device API, with example lowering on Hexagon to the HexagonUserDMA class. The example test case contained in this PR creates a 2 stage pipeline which lowers to the following TIR which is built and run on Hexagon.

[TejashShah]

cc @kparzysz-quic @jverma-quic

[adstraw]

@tvm-bot rerun

[adstraw]

@tvm-bot rerun

[github-actions]

Failed to re-run CI in https://github.com/apache/tvm/actions/runs/3091706323

Traceback (most recent call last):
  File "/home/runner/work/tvm/tvm/ci/scripts/git_utils.py", line 121, in _request
    with request.urlopen(req, data) as response:
  File "/usr/lib/python3.8/urllib/request.py", line 222, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib/python3.8/urllib/request.py", line 531, in open
    response = meth(req, response)
  File "/usr/lib/python3.8/urllib/request.py", line 640, in http_response
    response = self.parent.error(
  File "/usr/lib/python3.8/urllib/request.py", line 569, in error
    return self._call_chain(*args)
  File "/usr/lib/python3.8/urllib/request.py", line 502, in _call_chain
    result = func(*args)
  File "/usr/lib/python3.8/urllib/request.py", line 649, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 403: Forbidden

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "ci/scripts/github_tvmbot.py", line 574, in comment_failure
    raise item
  File "ci/scripts/github_tvmbot.py", line 685, in run
    pr.rerun_github_actions()
  File "ci/scripts/github_tvmbot.py", line 563, in rerun_github_actions
    raise e
  File "ci/scripts/github_tvmbot.py", line 555, in rerun_github_actions
    actions_github.post(f"actions/runs/{workflow_id}/rerun-failed-jobs", data={})
  File "/home/runner/work/tvm/tvm/ci/scripts/git_utils.py", line 143, in post
    return self._request(self.base + url, data, method="POST")
  File "/home/runner/work/tvm/tvm/ci/scripts/git_utils.py", line 126, in _request
    raise RuntimeError(f"Error response: {msg}\n{error_data}")
RuntimeError: Error response: HTTP Error 403: Forbidden
{"message":"This workflow is already running","documentation_url":"https://docs.github.com/rest/reference/actions#re-run-workflow-failed-jobs"}

[tmoreau89]

Thanks @adstraw, @JosephTheOctonaut and @masahi for the PR and the reviews, the PR has been merged!