fix folly tests in getdeps --shared-lib build

Summary:
X-link: facebook/folly#2539

Fix folly tests when run with --shared-libs and add CI for it so that the tests register with testx.

Motivation:  the folly python/cython extensions require that folly is built in shared library mode, and thrift-python requites folly python/cython

Reviewed By: bigfootjon

Differential Revision: D88502996

fbshipit-source-id: 2846bb9ed60fb59722d1aac99ab0661edc13fd87

Author: ahornby

build/fbcode_builder/getdeps.py

@@ -1180,6 +1180,9 @@ def write_job_for_platform(self, platform, args):  # noqa: C901
             if override_build_type:
                 build_type_arg = f"--build-type {override_build_type} "
 
+            if args.shared_libs:
+                build_type_arg += "--shared-libs "
+
             if build_opts.free_up_disk:
                 free_up_disk = "--free-up-disk "
                 if not build_opts.is_windows():