Some general changes to test framework and shared test code

See merge request nexedi/erp5!1936

this happens with new ghostscript, but this does not seem a critical
problem.

The test was only testing with empty cache

This should not happens, but if this happens we should not just return
in the middle of the loop, because this returned value is not used,
so we would just silently edit partially.

The first commit of this merge request was introduced for zope4py3 branch but it revealed issues on py2 as well, i.e. we don't have roles in auto-generated tester methods.

```
======================================================================
FAIL: test_method_protection (testSecurity.TestSecurity)
This test will list all implicitly Public methods in any objects in ZODB.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/(SR)/parts/erp5/Products/ERP5/tests/testSecurity.py", line 113, in test_method_protection
    self.fail(message)
AssertionError: 
The following 7 methods have a docstring but have no security assertions.
	/(SR)/parts/erp5/product/ERP5Form/PreferenceTool.py:65 isPreferredVcsPushMode
	/srv/slapgrid/slappart19/t/eiy/soft/8a7759fd7b65b20d9f87713605745d05/parts/erp5/product/ERP5Type/Accessor/AcquiredProperty.py:217 hasTelephoneValidationState
	/(SR)/parts/erp5/product/ERP5Type/Accessor/Base.py:219 hasViewFormIdList
	/(SR)/parts/erp5/product/ERP5Type/Accessor/Constant.py:94 isWebDocumentType
	/(SR)/parts/erp5/product/ERP5Type/Accessor/Content.py:224 hasImage
	/(SR)/parts/erp5/product/ERP5Type/Accessor/ContentProperty.py:283 hasImageWidthList
	/(SR)/parts/erp5/product/ERP5Type/Accessor/Translation.py:233 hasFrTranslatedTitle

----------------------------------------------------------------------
```

See merge request nexedi/erp5!1911

If a transaction is selected but instead of having accounts as
source/destination on lines it acquires the organisation set as
source/destination on the transaction, this causes an AttributeError
getGapList when trying to use this organisation as an account.

To fix this, adjust the getMovementHistoryList parameters to select only
lines using accounts, by passing node_uid, which is O(n) on the number
of accounts, but the number of accounts is not supposed to be too large
and other reports also do this assumption.

This prevents one failing test to make all subsequent tests to fail

this is removed from python3, it was not so useful here either

use sys.maxsize, see discussion on
nexedi/erp5!1751 (comment 203735)

assertCountEqual is the new python3 name.

Implement this in backportUnittest.py and also move the existing similar
patches (assertRaisesRegex and assertRegex).

  - move the logic of uploading to WebDAV server here instead of the
 generated bin/runUnitTest wrapper
  - run a new `coverage_report` which will
    - download all coverage data from WebDAV server
    - combine the data
    - run html report, saved in log folder
    - print text output in the text output.

This `coverage_report` test waits for other tests to finish uploading
data, we could extend test node distributor to distribute this test at
the end.

See merge request !1933

See merge request !1903

Move `spawnDrone` function (where user code is evaluated) and rename
used variables to avoid conflicts with the variables used by the user.
Previously if an user would have assign a value to `i` without declaring
the variable first, it would not have thrown any error as `i` was
already existing in the execution scope.

Even if null speed only makes sense for VTOL vehicules, it is a required testing feature as long as there is no dedicated API.

Loop interval is the time in milliseconds between 2 executions of the
onUpdate function of the user script as well as the periodicity to send
messages to the swarm (which means updating telemetry values).
As this is something we can set in SlapOS mostly to handle bandwith
usage, this must not be linked to the time delta used to update drone
position in the simulation.

Introduce `_callSetTargetCommand` function to regroup contraints on
command calls. Commands like `takeOff` and `land` should have such
constraints and therefore use `_internal_setTargetCoordinates` directly.

Timeout feature was broken by 2f7689d1 .

Add timeout check in tests.

 - str() because in ERP5JS the duration are directly serialized to json,
   which is not allowed.
 - int() to have a second level precision, which is more readable.

this is not used and cause a SyntaxWarning

This was based on libraries that were never ported to python3. If this
is still needed, it would have to be reimplemented with other newer
technologies.

See merge request !1932

Use same label as the action, "Preview"