hp2ps: fix invalid PostScript for names with parentheses
hp2ps: fix invalid PostScript for names with parentheses

The names in the .hp files may contain un-matched opening parentheses,
so escape them.

GHC Trac: #9517

Reviewers: bgamari, austin

Reviewed By: bgamari, austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2398

GHC Trac Issues: #9517

(cherry picked from commit 5df92f6776b31b375a80865e7db1f330d929c18f)

GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc