remove the ValueEnumerator utility

It's not needed anymore

Author: eeckstein

include/swift/Basic/ValueEnumerator.h

@@ -34,7 +34,6 @@ add_swift_unittest(SwiftBasicTests
   TransformRangeTest.cpp
   TypeLookupError.cpp
   UnicodeTest.cpp
-  ValueEnumeratorTest.cpp
   ${generated_tests}
   )
 

unittests/Basic/CMakeLists.txt

@@ -12,7 +12,6 @@
 
 #include "swift/Basic/OptionSet.h"
 #include "swift/Basic/Range.h"
-#include "swift/Basic/ValueEnumerator.h"
 #include "gtest/gtest.h"
 
 using namespace swift;

unittests/Basic/OptionSetTest.cpp

@@ -12,7 +12,6 @@
 
 #include "swift/Basic/Range.h"
 #include "swift/Basic/OptionSet.h"
-#include "swift/Basic/ValueEnumerator.h"
 #include "gtest/gtest.h"
 
 using namespace swift;