Fix CI: remove expected blank lines between switch cases in two more tests

TestSelectCaseComparesCharsAndStrings and CastToSameTypeAsync expected
blank lines between switch sections that were previously produced by
the Roslyn formatter when cases had block bodies. After #1244 removes
those blocks, the blank lines are no longer emitted.

https://claude.ai/code/session_01AkwUvu3XuCdj3D4axoX4UX

Author: claude

Tests/CSharp/MissingSemanticModelInfo/ExpressionTests.cs

@@ -294,7 +294,6 @@ public void PositionEnumFromString(char c)
             case '.':
                 Console.WriteLine(1);
                 break;
-
             case ',':
                 Console.WriteLine(2);
                 break;

Tests/CSharp/TypeCastTests.cs

@@ -1382,7 +1382,6 @@ private void Q()
         {
             case var @case when ""x"" <= @case && @case <= ""y"":
                 break;
-
             case ""b"":
                 break;
         }