[tests] Delete temporary const tests

These tests acted as a guard to make sure we didn't unintentionally enable control flow and spread
in const collections when we initially shipped the features. Now that we are getting close to
enabling them for const they no longer valid.

Added a few more compile-time errors to the const spread error suite.

Change-Id: I52e215d4c1c4394f1a1b868c05241277b0d58d2a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/108680
Reviewed-by: Bob Nystrom <[email protected]>
Commit-Queue: Nicholas Shahan <[email protected]>

Author: nshahan

tests/language_2/control_flow_collections/if_const_syntax_error_test.dart

@@ -10,6 +10,7 @@ import 'helper_classes.dart';
 
 var nonConstList = <int>[];
 var nonConstMap = <int, String>{};
+var nonConstSet = <int>{};
 const dynamic nonIterable = 3;
 const dynamic nonMap = 3;
 
@@ -48,20 +49,22 @@ void testMap() {
 void testSet() {
   // Must be constant.
   const _ = <int>{...nonConstList}; //# 09: compile-time error
+  const _ = <int>{...nonConstSet}; //# 10: compile-time error
 
   // Must be iterable.
-  const _ = <int>{...nonIterable}; //# 10: compile-time error
+  const _ = <int>{...nonIterable}; //# 11: compile-time error
 
   // Cannot be custom iterable type.
-  const _ = <int>{...ConstIterable()}; //# 11: compile-time error
+  const _ = <int>{...ConstIterable()}; //# 12: compile-time error
 
   // Cannot override operator.==().
   const obj = 0.1;
-  const _ = {...[0.1]}; //# 12: compile-time error
-  const _ = {...[Duration(seconds: 0)]}; //# 13: compile-time error
-  const _ = {...[obj]}; //# 14: compile-time error
+  const _ = {...[0.1]}; //# 13: compile-time error
+  const _ = {...[Duration(seconds: 0)]}; //# 14: compile-time error
+  const _ = {...[obj]}; //# 15: compile-time error
 
   // Cannot have collision.
-  const _ = {1, ...[1]}; //# 15: compile-time error
-  const _ = {...[1], ...[1]}; //# 16: compile-time error
+  const _ = {1, ...[1]}; //# 16: compile-time error
+  const _ = {...[1, 1, 3, 8]}; //# 17: compile-time error
+  const _ = {...[1], ...[1]}; //# 18: compile-time error
 }