Fix <rdar://problem/10255403> match_results::begin() is off by one

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@141494 91177308-0d34-0410-b5e6-96231b3b80d8

include/regex

diff --git a/include/regex b/include/regex
index 5e19569..760f4eb 100644
--- a/include/regex
+++ b/include/regex
@@ -5210,11 +5210,11 @@
     const_reference suffix() const {return __suffix_;}
 
     _LIBCPP_INLINE_VISIBILITY
-    const_iterator begin() const {return empty() ? __matches_.end() : __matches_.begin() + 1;}
+    const_iterator begin() const {return empty() ? __matches_.end() : __matches_.begin();}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator end() const {return __matches_.end();}
     _LIBCPP_INLINE_VISIBILITY
-    const_iterator cbegin() const {return empty() ? __matches_.end() : __matches_.begin() + 1;}
+    const_iterator cbegin() const {return empty() ? __matches_.end() : __matches_.begin();}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator cend() const {return __matches_.end();}