Read the source and the expected output of simple core tests from seperate files

This set of commits moves the source and the expected output of simple core tests to separate files.
I intend to do some extra work, based on these commits, to simplify and organize the emscripten tests.

I tested every single change on every single test which I modified. I avoided to change tests for which I wasn't
sure whether the outcome is platform dependent. The files which hold the expected output for each test, have been
dumped, as they were, from the python strings. This explains the newline warnings in some tests (they are 
harmless, as far as I can tell).