Shrink DynTypedNode by one pointer from 40 to 32 bytes (on x86_64).

The MemoizationData cache was introduced to avoid a series of enum
compares at the cost of making DynTypedNode bigger. This change reverts
to using an enum compare but instead of building a chain of comparison
the enum values are reordered so the check can be performed with a
simple greater than. The alternative would be to steal a bit from the
enum but I think that's a more complex solution and not really needed
here.

I tried this on several large .cpp files with clang-tidy and didn't
notice any performance difference. The test change is due to matchers
being sorted by their node kind.

Differential Revision: http://reviews.llvm.org/D13946

llvm-svn: 250905