In scope of this commit new GitHub Actions workflows for testing
Tarantool on M1 hosts are added:

  Release: .github/workflows/osx_arm64_11_2.yml
  Debug: .github/workflows/osx_debug_arm64_11_2.yml

Since GitHub Actions uses x86_64 environment by default on M1 targets,
'arch -arm64' prefix is specified in GitHub Actions workflow to make all
commands in .travis.mk run in ARM64 environment.

Introduced a new temporary target in .travis.mk Makefile to run only
specific LuaJIT test suites on M1. Now it runs only the following LuaJIT
test targets:
* PUC-Rio-Lua-5.1-tests
* lua-Harness-tests
* tarantool-tests

Python 3.9 is installed by default on M1 hosts, but gevent is required
for Tarantool tests, which installation fails with the following error:

  Using cached gevent-21.1.2.tar.gz (5.9 MB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... error
    ERROR: Command errored out with exit status 1:
     command: /opt/homebrew/opt/python@3.9/bin/python3.9 /opt/homebrew/lib/python3.9/site-packages/pip/_vendor/pep517/in_process/_in_process.py prepare_metadata_for_build_wheel /var/folders/b0/1vlv5rvn77x2rn6zbl2p4tqr0000gp/T/tmpyy59ae2p
         cwd: /private/var/folders/b0/1vlv5rvn77x2rn6zbl2p4tqr0000gp/T/pip-install-msbf7_vz/gevent_c2956687bb0d4de9bfb5f0660da759ee
    Complete output (42 lines):
      ...
      File "/private/var/folders/b0/1vlv5rvn77x2rn6zbl2p4tqr0000gp/T/pip-build-env-1lesbbxi/overlay/lib/python3.9/site-packages/cffi/api.py", line 48, in __init__
        import _cffi_backend as backend
    ImportError: dlopen(/private/var/folders/b0/1vlv5rvn77x2rn6zbl2p4tqr0000gp/T/pip-build-env-1lesbbxi/overlay/lib/python3.9/site-packages/_cffi_backend.cpython-39-darwin.so, 2): no suitable image found.  Did find:
    	/private/var/folders/b0/1vlv5rvn77x2rn6zbl2p4tqr0000gp/T/pip-build-env-1lesbbxi/overlay/lib/python3.9/site-packages/_cffi_backend.cpython-39-darwin.so: mach-o, but wrong architecture
    	/private/var/folders/b0/1vlv5rvn77x2rn6zbl2p4tqr0000gp/T/pip-build-env-1lesbbxi/overlay/lib/python3.9/site-packages/_cffi_backend.cpython-39-darwin.so: mach-o, but wrong architecture

This issue is described in gevent/gevent#1721. Fortunately, gevent can
be successfully installed via Python 3.8, hence to avoid this failure,
python3 is pinned to the specific version (i.e. python@3.8) until the
mentioned issue is resolved.

Closes tarantool/tarantool-qa#120
Relates to #6068