Add another missing header that used to be included transitively.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230927 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ProfileData/CoverageMapping.h

@@ -23,6 +23,7 @@
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/raw_ostream.h"
 #include <system_error>
+#include <tuple>
 
 namespace llvm {
 class IndexedInstrProfReader;