Build simple_embedding test via CMake

Closes https://github.com/google/iree/pull/407

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/iree/pull/407 from marbre:cmake-samples 95657c63dbf26afe5f3cdb4e532c9d9d53dbc336
PiperOrigin-RevId: 288726476
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a203999..bd22e94 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -115,6 +115,7 @@
 
 add_subdirectory(iree/base)
 add_subdirectory(iree/hal)
+add_subdirectory(iree/modules)
 add_subdirectory(iree/schemas)
 add_subdirectory(iree/testing)