Debug Info: code clean up.

Since we never insert DIE for DITemplateTypeParameter to a map, there is no need
to call getDIE in getOrCreateTemplateTypeParameterDIE. It is also renamed to
constructTemplateTypeParameterDIE to match with other construct functions
in CompileUnit.

Same applies to getOrCreateTemplateValueParameterDIE.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193287 91177308-0d34-0410-b5e6-96231b3b80d8