build(cross): Not null smartcast for locals

Author: Danielku15

src.compiler/csharp/CSharpEmitterContext.ts

@@ -1481,9 +1481,7 @@ export default class CSharpEmitterContext {
 
         if (
             symbol.flags & ts.SymbolFlags.Interface ||
-            symbol.flags & ts.SymbolFlags.Class ||
-            symbol.flags & ts.SymbolFlags.BlockScopedVariable ||
-            symbol.flags & ts.SymbolFlags.FunctionScopedVariable
+            symbol.flags & ts.SymbolFlags.Class
         ) {
             return false;
         }