tests: More refactoring, add helper header to every test, override exit for better error reporting

tests: Work on more thorough error handling

tests: Replace returns with exits in the main functions
This will allow us to redefine the exit function.

For example:
```
#define exit(code) { \
fprintf(stderr, "%s:%d: exit(%s) in function ‘%s

tests: Replace returns with exits in the main functions
This will allow us to redefine the exit function.

For example:
```
#define exit(code) { \
fprintf(stderr, "%s:%d: exit(%s) in function ‘%s’\n",
__FILE__, __LINE__, #code, __func__); \
_exit(code); \
}
```

show more ...

tests: Portability fixes, replaced 0/1/-1 return codes with macros

tests: Fix function signatures

Remove an accidentally committed binary. Again. Sigh.

Implement getrusage on linux