[test] Add dependency to the embedded-stdlib (#70215)

When not building `all`, like the `build-script` does in CI, the tests
did not have a dependency on `embedded-stdlib`, and those tests will
fail to pass if one was using CMake/Ninja to execute the tests after
something like `ninja clean`.

The dependency is added if the embedded stdlib is being built.

Author: drodriguez

test/CMakeLists.txt

@@ -311,6 +311,10 @@ foreach(SDK ${SWIFT_SDKS})
         endif()
       endif()
 
+      if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB AND TARGET "embedded-stdlib")
+        list(APPEND test_dependencies "embedded-stdlib")
+      endif()
+
       if(NOT "${COVERAGE_DB}" STREQUAL "")
         list(APPEND test_dependencies "touch-covering-tests")
       endif()