tests2: rework 117..119 to follow our conventions

tests2: rework 117..119 to follow our conventions

Please respect some conventions:

- tests2 filenames don't end with '..._test'

- tests2 tests are meant to produce some output

- the output should be somehow informative, not just
  "error" or "dummy". Because other people would want to
  know where it fails if it does.

- tests2 tests should work with both GCC and TCC, except
  if there are specifc reasons (like testing tcc-only
  feature such as bounds checking)

- tests2 tests should never crash or abort.  Because that
  would cause gui dialogs to pop up on windows, and because
  other people would not know where it fails if it does.

- tests2 tests should be somehow specific, in general.
  (rather than just collections of random stuff)

- in general, do not use 'long' if you mean 'larger than int'
  Because it isn't on many platforms.

- use four (4) spaces for block indention.  Do not insert
  tab characters in files if possible.

Also:
- tccgen.c:gen_cast() simplify last fix.