[CMake] Add llvm-profgen to LLVM_TEST_DEPENDS

Otherwise `check-llvm-*` may not rebuild llvm-profgen, causing llvm-profgen tests
to fail if llvm-profgen happens to be stale.
diff --git a/llvm/test/CMakeLists.txt b/llvm/test/CMakeLists.txt
index 4263937..691a7e1 100644
--- a/llvm/test/CMakeLists.txt
+++ b/llvm/test/CMakeLists.txt
@@ -102,6 +102,7 @@
           llvm-opt-report
           llvm-pdbutil
           llvm-profdata
+          llvm-profgen
           llvm-ranlib
           llvm-rc
           llvm-readobj