Add 'inline' but not 'always_inline' to std::strings destructor.

Adding both 'inline' and 'always_inline' to the destructor has been contentious.
However most of the performance benefits can be gained by only adding 'inline',
and there is no reason to hold up that change while discussing the other.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@285538 91177308-0d34-0410-b5e6-96231b3b80d8

include/string

@@ -806,7 +806,7 @@ public:
     basic_string(initializer_list<value_type> __il, const allocator_type& __a);
 #endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
 
-    ~basic_string();
+    inline ~basic_string();
 
     _LIBCPP_INLINE_VISIBILITY
     operator __self_view() const _NOEXCEPT { return __self_view(data(), size()); }