The Redeclarable part of named decls is read before their name.

The Redeclarable part of named decls is read before their name.
Lookup can nevertheless find them due to the serialized lookup table.
For instance when reading a template decl's templatedDecl, it will search for existing decls that it could be a redeclaration of, and find the half-read template decl.
Thus there is no point in asserting the names of decls.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164932 91177308-0d34-0410-b5e6-96231b3b80d8