[API] Dropping support for wiki_multilingual and wiki_cn

[leezu]

Description

This adds tests to prevent #753 from happening again.
While the two models are currently deprecated, they need nevertheless to be tested until support is completely dropped.

Checklist

Essentials

• PR's title starts with a category (e.g. [BUGFIX], [MODEL], [TUTORIAL], [FEATURE], [DOC], etc)
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage
• Code is well-documented

Comments

Fixes #753

[codecov]

Codecov Report

Merging #764 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #764      +/-   ##
=========================================
+ Coverage   90.69%   90.7%   +0.01%     
=========================================
  Files          64      64              
  Lines        6113    6110       -3     
=========================================
- Hits         5544    5542       -2     
+ Misses        569     568       -1

Impacted Files	Coverage Δ
src/gluonnlp/model/bert.py	100% <ø> (+0.72%)	⬆️
src/gluonnlp/data/utils.py	74.14% <ø> (ø)	⬆️

[codecov]

Codecov Report

❗ No coverage uploaded for pull request head (addbertmodeltests@9d5068e). Click here to learn what that means.
The diff coverage is n/a.

[mli]

Job PR-764/2 is complete.
Docs are uploaded to http://gluon-nlp-staging.s3-accelerate.dualstack.amazonaws.com/PR-764/2/index.html

[mli]

Job PR-764/4 is complete.
Docs are uploaded to http://gluon-nlp-staging.s3-accelerate.dualstack.amazonaws.com/PR-764/4/index.html

[mli]

Job PR-764/5 is complete.
Docs are uploaded to http://gluon-nlp-staging.s3-accelerate.dualstack.amazonaws.com/PR-764/5/index.html