Include the way string in the file name for dump files.

When compiling ghc the dump files for profiled and non-profiled artefacts used to always overwrite each other. This is tragic when you need the dump for the way that has been written.

I wrote up a patch that now by default includes the way in the file names for dump files. E.g. Main.p.dump-simpl.

The only thing I'm not sure about is weither or not it should be on by default.

I lean towards yes because:

• It minimizes risk of someone looking at the "wrong" dump file without realizing.
• If someone forgets to add the flag they don't have to restart their build.

Patch in !7998 (closed)