swift234

Iterate over more documented operators, now that the documentation has improved; now 3460 tests.
Replace hard-coded lists of real-number types, and of arithmetic and logical operators I’m testing, with lists added to SwiftIntTypes.py, which becomes a bit of a misnomer.  
Separate them into ones which only work on integer types, and those which also allow reals.
Do a double loop, over just the integers and then the reals as well.
Change the run line to allow importing StdlibUnittest with help from Dmitri, which I won't actually need until I do result type checking.

Approved by Dmitri.

Swift SVN r24029