Now that C++17 is official (https://www.iso.org/standard/68564.html), start changing the C++1z terminology over to C++17. NFC intended, these are all mechanical changes.

llvm-svn: 319688
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 3fe50db..56b14dd 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -5750,7 +5750,7 @@
   // happen in C++17, because it would mean we were computing the composite
   // pointer type of dependent types, which should never happen.
   if (EST1 == EST_ComputedNoexcept || EST2 == EST_ComputedNoexcept) {
-    assert(!S.getLangOpts().CPlusPlus1z &&
+    assert(!S.getLangOpts().CPlusPlus17 &&
            "computing composite pointer type of dependent types");
     return FunctionProtoType::ExceptionSpecInfo();
   }