+ corresponding bits in golang.testing package.

py.bench description follows:

"""
py.bench, similarly to py.test, discovers bench_* functions and Bench* classes
and then runs each discovered benchmark via golang.testing.benchmark. Similarly
to `go test -bench`, benchmarking results are printed in Go benchmark format.

For example, running py.bench on the following code::

    def bench_add(b):
        x, y = 1, 2
        for i in xrange(b.N):
            x + y

gives something like::

    $ py.bench --count=3 x.py
    ...
    pymod: bench_add.py
    Benchmarkadd    50000000        0.020 µs/op
    Benchmarkadd    50000000        0.020 µs/op
    Benchmarkadd    50000000        0.020 µs/op
"""

The implementation is based on t/py.bench from Wendelin.core - see
following commits for its history:

lab.nexedi.com/nexedi/wendelin.core/commit/51f252d4
lab.nexedi.com/nexedi/wendelin.core/commit/074ce24d
lab.nexedi.com/nexedi/wendelin.core/commit/ed13c3f9
lab.nexedi.com/nexedi/wendelin.core/commit/fc08766d
lab.nexedi.com/nexedi/wendelin.core/commit/5a1ed45a
lab.nexedi.com/nexedi/wendelin.core/commit/bcab1246

Python3 complains that there is no .im_func & friends of a method.
Workaround it all with compat code.

This patch made its first step as a way to teach qq to also work on
python3. However the differences in str / unicode and escapes in between
py2 / py3 quickly popped out and then it became easier to just handle
whole escaping logic myself.

The implementation is based on

	kirr/go123@c0bbd06e

and byproduct of manual handling is that now we don't escape printable
UTF-8 characters.

Go benchmark format is described here:

	https://github.com/golang/proposal/blob/master/design/14313-benchmark-format.md

Additionally we support extension to that format:

	- a line starting with `*** neotest:` denotes start of neotest extension block.
	  The block consists of labels describing e.g. hardware and software on a node.
	  The block ends with a blank line.
	  Labels in the block are not added to benchmarking lines from main stream.
	  The block itself should not contain benchmark lines.

and upon processing benchmark units are normalized to common base,
similarly to

	golang.org/cl/82955
	golang.org/cl/82956
	golang.org/cl/82957

Orignally implemented here:

	neo@502d9477
	neo@a9b10a45
	neo@f5fec740
	neo@916782b6

Not only we can import modules by full path, but now we can also spawn
threads/coroutines and exchange data in between them with the same
primitives and semantic as in Go.

The bulk of new functionality is copied from here:

	kirr/go123@9e1aa6ab

Original commit description follows:

"""
golang: New _Python_ package to provide Go-like features to Python language
- `go` spawns lightweight thread.
- `chan` and `select` provide channels with Go semantic.
- `method` allows to define methods separate from class.
- `gimport` allows to import python modules by full path in a Go workspace.

The focus of first draft was on usage interface and on correctness, not speed.
In particular select should be fully working.

If there is a chance I will maybe try to followup with gevent-based
implementation in the future.
Hide whitespace changes
"""

Module gopath provides way to import python modules by full path in a Go workspace.

For example

    lonet = gopath.gimport('lab.nexedi.com/kirr/go123/xnet/lonet')

will import either

    lab.nexedi.com/kirr/go123/xnet/lonet.py, or
    lab.nexedi.com/kirr/go123/xnet/lonet/__init__.py

located somewhere under $GOPATH.

A simple project to allow python imports to be done by full path in a Go
workspace.