Fix PR 19663. Some calls to find(vector<bool>) were returning iterators that were subtly invalid (didn't compare equal). Thanks to Erik Verbruggen for the report (and diagnosis)

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@208096 91177308-0d34-0410-b5e6-96231b3b80d8

test/containers/sequences/vector.bool/find.pass.cpp

@@ -25,6 +25,7 @@ int main()
             std::vector<bool> b(i,true);
             std::vector<bool>::iterator j = std::find(b.begin()+1, b.end(), false);
             assert(j-b.begin() == i);
+            assert(b.end() == j);
         }
     }
     {
@@ -33,6 +34,7 @@ int main()
             std::vector<bool> b(i,false);
             std::vector<bool>::iterator j = std::find(b.begin()+1, b.end(), true);
             assert(j-b.begin() == i);
+            assert(b.end() == j);
         }
     }
 }