Mark instantiated function decls as inline specified if any pattern is

A function template pattern can be declared without the 'inline'
specifier and defined later with the 'inline' specifier. However, during
instantiation, we were only looking at the canonical decl to see if we
should mark the instantiated decl as inline specified. Since the
instantiated decl actually represents many pattern declarations, put the
inline specifier on the instantiation decl if any of the pattern decls
have it.

llvm-svn: 233817