Issue #28915: Replace _PyObject_CallMethodId() with
_PyObject_CallMethodIdObjArgs() when the format string only use the format 'O'
for objects, like "(O)".

_PyObject_CallMethodIdObjArgs() avoids the code to parse a format string and
avoids the creation of a temporary tuple.

Issue #28915: Without parenthesis, _PyObject_CallMethodId() avoids the creation
a temporary tuple, and so is more efficient.

Issue #28915: Use _Py_VaBuildStack() to build a C array of PyObject* and then
use _PyObject_FastCall().

The function has a special case if the stack only contains one parameter and
the parameter is a tuple: "unpack" the tuple of arguments in this case.

Issue #28915: Similar to Py_VaBuildValue(), but work on a C array of PyObject*,
instead of creating a tuple.

Issue #28915: Py_ssize_t type is better for indexes. The compiler might emit
more efficient code for i++. Py_ssize_t is the type of a PyTuple index for
example.

Replace also "int endchar" with "char endchar".

Issue #28915.

Issue #28915: Add _PyObject_CallFunctionVa() helper to factorize code of
functions:

* PyObject_CallFunction()
* _PyObject_CallFunction_SizeT()
* callmethod()

Issue #28915: Add _PyObject_FastCallVa() helper to factorize code of functions:

* PyObject_CallFunctionObjArgs()
* PyObject_CallMethodObjArgs()
* _PyObject_CallMethodIdObjArgs()

Inline objargs_mkstack() into _PyObject_FastCallVa(), remove
objargs_mkstack().

test_functools hanging on the Android armv7 qemu emulator.

This makes tests passing after changes by issue #5322.

Improve speed of dict literal with constant keys up to 30%.

Original patch by Andreas Stührk.

Original patch by Andreas Stührk.

and recreated in the 'r' and 'w' modes (will be an error in future Python
releases).

writes the index file when it is not changed.

writes the index file when it is not changed.

writes the index file when it is not changed.

Prepare for 3.6.1.  Any further 3.6.0 release candidates and 3.6.0 final will be cherrypicked and merged here.