NFC: Remove the ObjC1/ObjC2 distinction from clang (and related projects)

We haven't supported compiling ObjC1 for a long time (and never will again), so
there isn't any reason to keep these separate. This patch replaces
LangOpts::ObjC1 and LangOpts::ObjC2 with LangOpts::ObjC.

Differential revision: https://reviews.llvm.org/D53547

llvm-svn: 345637
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 0bf2578..f4687fe 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -5381,7 +5381,7 @@
   Expr *Initializer = nullptr;
   if (Args.size() == 1) {
     Initializer = Args[0];
-    if (S.getLangOpts().ObjC1) {
+    if (S.getLangOpts().ObjC) {
       if (S.CheckObjCBridgeRelatedConversions(Initializer->getBeginLoc(),
                                               DestType, Initializer->getType(),
                                               Initializer) ||