This is similar to the LibJS test data that resides in
/home/anon/js-tests.
It's more convenient than storing the test programs as raw strings
in the code.
This feels like a better name since the "autocomplete engine" can, in
addition to providing autocomplete suggestions, also find declarations
of symbols and report back the symbols that are defined in a document.
Also, Cpp/ParserAutoComplete has been renamed to CppComprehensionEngine
and Shell/AutoComplete has been renamed to ShellComprehensionEngine.
The Cpp LanguageServer tests can be run with: CppLanguageServer -t
The tests now only cover some very simple autocomplete and
"find declaration" use cases, but it's a start :)
