Build a new runner image with packages from the recent rolling stable
release 821.
Newly skipped tests are tracked in #797, #800.
Pass rate: 92.76% -> 92.6%

Introducing a new approach for skipping tests. Skip lists are located in
the directory `scripts/skiplist`. Currently there are two skip lists:

* `scripts/skiplist/default` - default, tests to skip in the main
workflow and by `test-triton.sh` script.
* `scripts/skiplist/conda` - tests to skip in the conda workflow
(currently it requires more tests to skip).

In future, it is possible to add more skip lists. To specify a custom
skip list set `TRITON_TEST_SKIPLIST_DIR` before executing
`test-triton.sh`, for example, conda workflow sets this to use a custom
skip list:

```
TRITON_TEST_SKIPLIST_DIR=scripts/skiplist/conda
```

Every skip list can contain 0 or more `.txt` files, each file
corresponds to a "test suite". The whole list of existing test suites
can be obtained from `test-triton.sh` by searching for different values
of `TRITON_TEST_SUITE`, for example:

```
TRITON_DISABLE_LINE_INFO=0 TRITON_TEST_SUITE=line_info \
pytest --verbose --device xpu language/test_line_info.py
```

Currently there are 7 "tests suites":

* `language`
* `subprocess`
* `runtime`
* `line_info`
* `interpreter`
* `operators`
* `regression`

For example, if you want to skip a test in a "subprocess" test suite,
add a line with the fully qualified test name to
`scripts/skiplist/default/subprocess.txt`:

```
# This is a comment. Please use comments to specify why next tests are skipped, for example
# #800
test/unit/language/test_subprocess.py::test_print[print-int32]
```

If a `.txt` file for a test suite does not exist, or empty then no tests
will be skipped. To get a full list of the available tests for a test
suite, use `pytest` with `--collect-only`, for example:

```
$ pytest --collect-only language/test_subprocess.py -q | sort
33 tests collected in 0.01s
test/unit/language/test_subprocess.py::test_assert[assert]
test/unit/language/test_subprocess.py::test_assert[device_assert]
...
```

This PR contains only several tests to skip (see
`scripts/skiplist/default/subprocess.txt`), see #800. The corresponding
Python code to skip tests programmatically has been removed from
`test_subprocess.py`. If this works, we can gradually populate the
default skip list by removing code to skip from Python files.

Note that an error will be generated if you try to skip a test that does
not exists. This is intendent behavior (we use
`--select-fail-on-missing` for
[pytest-select](https://pypi.org/project/pytest-select/)) and required
to calculate a pass rate.

Closes #800

I accidentally discovered this effect while I was working on
#1082. It
seems that accessing the tensor elements via `repr` builtin python
function stimulates the execution of the kernel and obtaining output
from it.

Although the behavior is different from other backends, it allows us to
at least somehow test this feature right now.

---------

Signed-off-by: Anatoly Myachev <[email protected]>

Closes intel#800

Signed-off-by: Kirill Suvorov <[email protected]>