CP #35354: Add CO_FUTURE_PRINT_FUNCTION and CO_FUTURE_UNICODE_LITERALS to compile().
CP #35469: Fix compile with missing filename and -X:Tracing.

With -X:Tracing, compile does not work without a filename (there's a lookup into a debug info map). Use a dummy name instead.
Fix sys.prefix in Debug builds.

Remove special-casing of Debug builds and copy os.py to build directory.

Probably need to copy the entire stdlib but will try to find a better solution.
Change exception thrown when .pop() is called on an empty bytearray to match CPython.
Change exception message for unsubscriptable objects to match CPython.
Add final newline to expected exception message.
Add the stdlib when running tests from a checkout.
Partial fix for CP21478.
Merge branch 'ipy-2.7-maint' of github.com:IronLanguages/main into ipy-2.7-maint