Cleaning up compiler warnings

When compiling Kona using the clang compiler on OSX there were many warnings generated. These fell into two main classes: complaints about control structures with empty bodies and complaints about the use of presumed format string characters in Kona's tests. The following is a good example of the former:

    src/0.c:920:34: warning: while loop has empty body [-Wempty-body]
      while(!(z=read_tape(sockfd,1)));

And the following is an example of the latter:

    src/tests.c:1134:3: warning: data argument not used by format string [-Wformat-extra-args]
      TC(3 2, y:2 1; 1 2 3 4 y)
      ^~~~~~~~~~~~~~~~~~~~~~~~~

Format string warnings were resolved by restructuring the `TC_` macro slightly.

I ran the tests after making my modifications and this should have no impact on behavior. I don't think this strays too far from the existing style of the codebase.