Make constant static variables const so they can go into a read-only section

NFC.

llvm-svn: 231597
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 035dc73..d312e8d 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -642,11 +642,12 @@
       if (tryMergeTemplateString())
         return;
 
-      static tok::TokenKind JSIdentity[] = {tok::equalequal, tok::equal};
-      static tok::TokenKind JSNotIdentity[] = {tok::exclaimequal, tok::equal};
-      static tok::TokenKind JSShiftEqual[] = {tok::greater, tok::greater,
-                                              tok::greaterequal};
-      static tok::TokenKind JSRightArrow[] = {tok::equal, tok::greater};
+      static const tok::TokenKind JSIdentity[] = {tok::equalequal, tok::equal};
+      static const tok::TokenKind JSNotIdentity[] = {tok::exclaimequal,
+                                                     tok::equal};
+      static const tok::TokenKind JSShiftEqual[] = {tok::greater, tok::greater,
+                                                    tok::greaterequal};
+      static const tok::TokenKind JSRightArrow[] = {tok::equal, tok::greater};
       // FIXME: We probably need to change token type to mimic operator with the
       // correct priority.
       if (tryMergeTokens(JSIdentity))