Update Closure Compiler to v20180805

If you apply CLJS-2878.patch, tests pass on macOS and Windows but not on Linux (CI) with the following.

Note that Canary's Linux-based test with the latest Closure Compiler snapshot is passing.

It appears that the root cause of the CI problems was that the Travis CI box was temporarily running older versions of NPM/Node. You can repro the problem with a default install of Ubuntu 14.04, and you can even repro it without this patch.

fixed https://github.com/clojure/clojurescript/commit/9e1ff2232da00dcda7fb495784e7d5a1d72573a7