add another case to this test - += of a closure slot
update expected output
add some int64 const functions for ejsval bools
add @visitSpreadElement
add is_string_literal
lots of module fixes.  add SpreadElement to ComputeFree
some module import/export fixes, and try to do fewer LLVM alloca
remove debug spew
some niceties, and track change to compiler.gatherImports
objc_internal -> @objc_internal, and user modules again take the exports as arg0, it's not returned
remove some unused @opencode_intrinsics fields, and isBoolean shouldn't be using @createEjsBoolSelect, it should return the IR value.
no need to create Object_DefineProperty every time.