Fix a bunch of test TODOs.

- Added a bunch of tests.
- Removed some TODOs for stuff that's already done.
- Made list literals handle newlines better.

test/list/newlines.wren

@@ -0,0 +1,14 @@
+// Allow newlines in most places.
+var list = [
+
+"a"
+, "b",
+
+"c", "d"
+
+]
+
+io.write(list[0]) // expect: a
+io.write(list[1]) // expect: b
+io.write(list[2]) // expect: c
+io.write(list[3]) // expect: d