JS: Replaced fromCodePoint/codePointAt with fromCharCode/charCodeAt because of functions limited availability, fixed typo in tests.

Un-breaks users who have old generated code and upgrade
to the 3.1.0 release.

A bug was causing generated JSPB code with CommonJS-style imports to
refer incorrectly to nested messages from other .proto files. The
generated code would have things like "test_pb.InnerMessage" instead of
"test_pb.OuterMessage.InnerMessage". This commit fixes the problem by
correctly taking into account any message nesting.

[skip ci]

Change-Id: I1ba6f6372a08b5796570851336e1a548602f60da

Had to strip out some JSPB-format test code,
but also added some .proto test messages that
had been improperly stripped out.

Un-breaks users who have old generated code and upgrade
to the 3.1.0 release.

A bug was causing generated JSPB code with CommonJS-style imports to
refer incorrectly to nested messages from other .proto files. The
generated code would have things like "test_pb.InnerMessage" instead of
"test_pb.OuterMessage.InnerMessage". This commit fixes the problem by
correctly taking into account any message nesting.

[skip ci]

Change-Id: I1ba6f6372a08b5796570851336e1a548602f60da

Had to strip out some JSPB-format test code,
but also added some .proto test messages that
had been improperly stripped out.

Fix valueWriterFn_ variable name

This change will help us separate binary support into
separate files, because we only refer to binary serialization
functions in the actual binary serialization paths.

A couple of small tweaks were needed to fix test failures that were
inadvertently introduced in the last down integration. I also had to add
the map.js file which was missing.

This includes all internal changes from around May 20 to now.