Cleanup com/win32com/test/testall.py

[Avasam]

I was doing a few readability changes when debugging a failing test for #2502. But kept finding more and more to cleanup. So here it is all at once:

• Simplified __file__-related code
• Removed unused GenerateAndRunOldStyle
• Moved imports that don't need to be lazy to top of file
• Remove unused imports
• Use f-strings in favor of % printf-style format
• Use True insteadof 1 for boolean True
• Added annotations to help with IntelliSense
• Simplified import_failures to only contain the error instead of type + error instance
  • Also use the error directly instead of calling sys.exc_info()
• Printing once with a multiline string instead of printing multiple times
• Fixed make_test_suite not using the test_level parameter
• Fixed that test level 0 was a valid argument
• Wrap all lines at 88 characters
• Add an error message if multiple test level arguments are passed, rather than taking the last one.
• Add level 4 to usage string

Also done in other PRs (so merging those first will reduce changes here):

• Fixed typos (Fix typos, unknown utf8-chars, and capitalize GitHub in docs #2495)
• Use list literals instead of redundant call to str.split() (also done in Reduce usages of empty split() on literal strings #2438)

Given lots of tests don't run on the CI. This should be run locally.

Argument parsing behaviour change: