* Don't use the timestamp of an existing file anymore, only use fixed
  timestamp
* Enhance the code checking the resolution of the filesystem timestamps.
* Check timestamps with a resolution of 1 microsecond instead of 1 millisecond
* When os.utime() uses the current system clock, tolerate a delta of 20 ms.
  Before some os.utime() tolerated a different of 10 seconds.
* Merge duplicated tests and simplify the code

This is mostly a backport of issue #21907, but also includes a few
extras necessary to make the bulidbot scripts as thin as possible.

  string.Template instances.

Initial patch by Brandon Milam.

"cum" is not a valid argument.

Patch by Brandon Milam.

Ensure that the uninstall helper for Windows passes the proper
flags to pip to prevent it from checking PyPI if the pip that
we're currently attempting to uninstall is the latest verison.

does support IPv6 and IPv4; www.python.org currently does not.

PyObject_IsInstance(), PyObject_RichCompareBool() and _PyDict_Contains()
to check for and handle errors correctly.

Original patch by David Moore.

See also issue 24017.

fix a resource warning.