[CMake] Add llvm-config to DEBUGINFO_TEST_DEPS

Fix `fatal: Could not run process ['/path/to/build/./bin/llvm-config', '--build-mode']`
when running check-debuginfo in a fresh build directory.

GitOrigin-RevId: ca8b7ef763797253e08f614a7d38b76e77806b12
diff --git a/CMakeLists.txt b/CMakeLists.txt
index addf13d..dcd80bd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,6 +16,7 @@
   clang
   FileCheck
   count
+  llvm-config
   llvm-objdump
   check-gdb-llvm-support
   not