Split linking_tags.wast into two files

[frank-emrich]

This PR splits linking_tags.wast into two files.

This is a preparation step needed to land fast effect forwarding due to the following:
linking_tags.wast currently has two assert_suspension directives. In the current implementation, we are always on the main stack when we detect that a tag is unhandled and trap from there. However, in the presence of fast effect forwarding, we detect the lack of an appropriate handler at the suspend site and trap there (i.e., possibly while still running on a continuation stack).

As a result, the assert_suspension directives in linking_tags.wast trigger the problem described in #253 as soon as fast fowarding lands. As a workaround, this PR splits the file into two, where the assert_suspension is the very last step in each test (i.e., we avoid further execution inside the Store where we trapped while inside a continuation). The combined contents of both files is identical to the original linking_tags.wast, but the module bar is moved to the end of the second file.

[dhil]

LGTM.