Add missing checks for `templateParams:` in `MDCompositeType`. Pull the
current check for `MDSubprogram` to reduce duplicated code and fix it up
to print a good message when the immediate operand isn't an `MDTuple`
(as a drive-by, make the same fix to `variables:` in `MDSubprogram`).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234177 91177308-0d34-0410-b5e6-96231b3b80d8
