Proper errors for cases like 'is Map' supported in 'when'

idea/testData/quickfix/addStarProjections/when/afterUnqualifiedMapOneArg.kt

@@ -0,0 +1,9 @@
+// "Add '<*, *>'" "false"
+// "Add '<*>'" "false"
+// ERROR: 2 type arguments expected
+public fun foo(a: Any) {
+    when (a) {
+        is Map<Int> -> {}
+        else -> {}
+    }
+}