Merging r156031:

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r156031 | rsmith | 2012-05-02 15:22:32 -0700 (Wed, 02 May 2012) | 4 lines

Revert most of r154844, which was disabled in r155975. Keep around the
refactorings in that revision, and some of the subsequent bugfixes, which
seem to be relevant even without delayed exception specification parsing.

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llvm-svn: 156684