Update test commands

[happyhj]

Description

Currently, running $ yarn test --browsers=Chrome --grep='multinomial' don't filters tests.

The syntax to use to pass arguments to the package script running with yarn (run) has changed.

Because of this, the arguments that are passed to the yarn test which is posted in DEVELOPMENT.md are not applied to the karma start command.

So I updated the command to match the new syntax.

Please refer to the issue below
yarnpkg/yarn#1667

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For repository owners only:

Please remember to apply all applicable tags to your pull request.
Tags: FEATURE, BREAKING, BUG, PERF, DEV, DOC, SECURITY

For more info see: https://github.com/tensorflow/tfjs/blob/master/DEVELOPMENT.md

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This change is 

[nsthorat]

Which version of yarn are you using?

With yarn -v I get 1.5.1.

When I run this I get the following message:

warning From Yarn 1.0 onwards, scripts don't require "--" for options to be forwarded. In a future version, any explicit "--" will be forwarded as-is to the scripts.

In the issue that you linked, the user is using yarn version 0.16.1.

[tafsiri]

One fix could be to specify a minimum yarn version in the 'engines' entry of our package.json https://yarnpkg.com/en/docs/package-json#toc-engines. We could try >= 1.4.0 as a start.

[happyhj]

@nsthorat You're right. My yarn version was outdated. (v0.16.1) I updated yarn to v1.5.1 and it works like a magic. So I got the test commands back.

@tafsiri I think that is good idea to specify minimum yarn version. So I done that on my last commit.

[happyhj]

The travis CI's yarn version is v1.3.2. So I lowered the minimum yarn version to fix the error on CI.