refactor: restructure list/map compilation loops and extract syntax error tests

- Convert list() and map() compiler functions from if/do-while to do-while loops
- Remove redundant empty literal handling by breaking on right bracket/brace
- Add new test files for duplicate comma, duplicate trailing comma, and empty list/map with comma
- Expand newlines test to cover trailing comma and empty list/map cases
- Simplify trailing_comma tests by removing inline syntax error checks
- Update Test.fail() to handle variable arguments without kwargs

test/language/map/newlines.wren

@@ -0,0 +1,27 @@
+// Allow after '{', ':', and ',', and before ']'.
+var map = {
+
+"a":
+
+"a value",
+
+"b": "b value"
+
+}
+
+IO.print(map["a"]) // expect: a value
+IO.print(map["b"]) // expect: b value
+
+// Newline after trailing comma.
+map = {"c": "c value",
+
+}
+
+IO.print(map["c"]) // expect: c value
+
+// Newline in empty map.
+map = {
+
+}
+
+IO.print(map.count) // expect: 0