Fix warning about uninitialized const member. NFC

llvm-svn: 272823

Author: EricWF

libcxxabi/test/catch_member_data_pointer_01.pass.cpp

@@ -22,6 +22,7 @@ typedef       int A::*md2;
 
 struct B : public A
 {
+    B() : k(42), l(0) {} // explicitly initialize 'k' to prevent warnings.
     const int k;
     int l;
 };