patch applied (testsuite): add negative-prim-literal tests

[Isaac Dupree]

Sat May 26 15:44:05 PDT 2007  Isaac Dupree <id at isaac.cedarswampstudios.org>
  * add negative-prim-literal tests
  the first for behavior common between their new and old parsings (passes both),
  the second to test the new behavior (fails before, passes after)

    M ./tests/ghc-regress/parser/should_run/all.T +2
    A ./tests/ghc-regress/parser/should_run/read002.hs
    A ./tests/ghc-regress/parser/should_run/read002.stdout
    A ./tests/ghc-regress/parser/should_run/read003.hs
    A ./tests/ghc-regress/parser/should_run/read003.stdout