Update CMake build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165908 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/ADT/CMakeLists.txt

@@ -13,6 +13,7 @@ set(ADTSources
   FoldingSet.cpp
   HashingTest.cpp
   ilistTest.cpp
+  ImmutableMapTest.cpp
   ImmutableSetTest.cpp
   IntEqClassesTest.cpp
   IntervalMapTest.cpp