Lexer: Support Microsoft suffix (u)i64

MSVC2010 supports all combinations of upper- and lowercase U/I.

Task-number: QTCREATORBUG-15554
Change-Id: I0106e6b5038a62aebe5a6c1eb0467d693befb4b0
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/libs/3rdparty/cplusplus/Lexer.cpp

@@ -853,6 +853,17 @@ bool Lexer::scanOptionalIntegerSuffix(bool allowU)
             scanOptionalIntegerSuffix(false);
         }
         return true;
+    case 'i':
+    case 'I':
+        yyinp();
+        if (_yychar == '6') {
+            yyinp();
+            if (_yychar == '4') {
+                yyinp();
+                return true;
+            }
+        }
+        return false;
     case 'l':
         yyinp();
         if (_yychar == 'l')