Remove duplicate _LIBCPP_INLINE_VISIBILITY attributes.

This attribute should appear only on the first declaration. This
patch cleans up <string> by removing the attribute on redeclarations.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@347608 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed