Add tests for getint, getdouble and getboolean methods of the tkapp object.
Issue #21552: Fixed possible integer overflow of too long string lengths in
the tkinter module on 64-bit platforms.
Test correct getXXX methods in Tkinter bigmem tests.
Tk.getint is just int, true Tk wrapper is available as Tk.tk.getint.
Issue #21608: Updated HTTPHandler documentation.
Issue #21593: (from StackOverflow) minor doc clarification for re.search.