[modules] Renumber DECL_UPDATES from 30 to 50, so it no longer collides with

TYPE_TEMPLATE_SPECIALIZATION. This was fine in practice because both record
kinds are only ever found by offset, but made the llvm-bcanalyzer -dump output
very confusing.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@263989 91177308-0d34-0410-b5e6-96231b3b80d8