Move Emit24 to clang::io

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@97569 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CacheTokens.cpp b/lib/Frontend/CacheTokens.cpp
index 7326937..09b5b45 100644
--- a/lib/Frontend/CacheTokens.cpp
+++ b/lib/Frontend/CacheTokens.cpp
@@ -190,12 +190,7 @@
 
   void Emit16(uint32_t V) { ::Emit16(Out, V); }
 
-  void Emit24(uint32_t V) {
-    Out << (unsigned char)(V);
-    Out << (unsigned char)(V >>  8);
-    Out << (unsigned char)(V >> 16);
-    assert((V >> 24) == 0);
-  }
+  void Emit24(uint32_t V) { ::Emit24(Out, V); }
 
   void Emit32(uint32_t V) { ::Emit32(Out, V); }