test_commonjs does not run test set equivalent to test_closure

[dibenede]

The test_commonjs gulp target runs this (jasmine.json](https://github.com/protocolbuffers/protobuf-javascript/blob/e34549db516f8712f678fcd4bc411613b5cc5295/commonjs/jasmine.json) that is notably missing most of the binary/ tests. Expanding the test set results in many function not found/undefined errors, even when using closure's SIMPLE_OPTIMIZATIONS level.

I'm guessing we need to add more @export tags and expand upon https://github.com/protocolbuffers/protobuf-javascript/blob/e34549db516f8712f678fcd4bc411613b5cc5295/commonjs/export_testdeps.js .

[dibenede]

Fixed in #146