Add inherited attributes before parsed attributes.

Currently, attributes from previous declarations ('inherited attributes')
are added to the end of a declaration's list of attributes. Before
r338800, the attribute list was in reverse. r338800 changed the order
of non-inherited (parsed from the current declaration) attributes, but
inherited attributes are still appended to the end of the list.

This patch appends inherited attributes after other inherited
attributes, but before any non-inherited attribute. This is to make the
order of attributes in the AST correspond to the order in the source
code.

Differential Revision: https://reviews.llvm.org/D50214

llvm-svn: 342861