Use TopLevelDeclarations analysis mode in REPL

#KT-12564 Fixed

compiler/testData/repl/controlFlow/incompleteWhen.repl

@@ -0,0 +1,11 @@
+>>> val a = when(null) { }
+error: 'when' expression must be exhaustive, add necessary 'else' branch
+val a = when(null) { }
+        ^
+warning: the expression is unused
+val a = when(null) { }
+             ^
+>>> "" + when (true) { true -> 42 }
+error: 'when' expression must be exhaustive, add necessary 'false' branch or 'else' branch instead
+"" + when (true) { true -> 42 }
+     ^