Move type converter unittests to separate binary

mojo/tools/data/unittests

 # This file contains a list of Mojo gtest unit tests.
 # This must be valid python. It can use the |config| global that will be a
 # mopy.config.Config object and must set a |tests| global that will contain the
 # tests to run.
 # TODO(vtl): Add a way of specifying data dependencies instead of cacheable.
 
 tests = [
   # EDK tests:
   {
     "test": "mojo_edk_embedder_unittests",
@@ skipping 30 matching lines @@
   {
     "test": "crypto_unittests",
   },
   {
     "test": "mojo_application_manager_unittests",
   },
   {
     "test": "mojo_common_unittests",
   },
   {
+    "test": "mojo_converters_unittests",
+  },
+  {
     "test": "mojo_view_manager_lib_unittests",
   },
   {
     "test": "mojo_surfaces_lib_unittests",
   },
   {
     "test": "url_response_disk_cache_unittests",
   },
   {
     "test": "view_manager_service_unittests",
@@ skipping 45 matching lines @@
       "cacheable": False,
     },
   ]
 
 if config.target_os == config.OS_LINUX:
   tests += [
     {
       "test": "sandbox_linux_unittests",
     },
   ]