Add support for whitespace control mustaches

See http://handlebarsjs.com/block_helpers.html#whitespace-control
move handlebars lexer to gen source root
regen handlebars
read action
introduce DartCommandLineRunnerParameters, use SkipDefaultValuesSerializationFilters
correct end offset calculation when startSymbol == endSymbol
ignore // interpolation start/end
#WEB-12149 fixed
WEB-12215 Reformat code adds a newline between function and documentation comment
replace @Nullable findInstance with @NotNull utility with logging (EA-55734)
don't register JsTestDriver server at startup (it will be registered on jstd test run)