Changes to ghc testsuite

Changes to ghc:
commit 3f6da561a9d71030efbab20544c4f77f9da0759d
Author: Joachim Breitner <mail@joachim-breitner.de>
Date:   Mon Dec 9 15:29:21 2013 +0000

    New flag: -ddump-strsigs

    The existing flag -ddump-stranal dumps the full Core, which is very
    verbose and not always helpful. This adds a more concise output (one
    line per top-level bind) that is faster to read, and especially more
    suitable to be used when writing test cases for the strictness analiser.

Changes to testsuite:
commit 323cab22d65ea88410a607ef22db23198c03e305
Author: Joachim Breitner <mail@joachim-breitner.de>
Date:   Mon Dec 9 15:40:20 2013 +0000

    Use -ddump-strsigs in tests/stranal/sigs

    because it is more reliable than the previous GHC plugin (no need to
    support annotations etc.), plus it works nicely with "make accept".