Fix for KT-16732: Type 'java/lang/Number' (current frame, stack[0]) is not assignable to 'java/lang/Character

#KT-16732 Fixed

compiler/testData/codegen/box/primitiveTypes/kt16732.kt

@@ -0,0 +1,15 @@
+//WITH_RUNTIME
+
+fun valueFromDB(value: Any): Any {
+    return when (value) {
+        is Char -> value
+        is Number-> value.toChar()
+        is String -> value.single()
+        else -> error("Unexpected value of type Char: $value")
+    }
+}
+
+fun box(): String {
+    valueFromDB(1)
+    return "" + valueFromDB("O") + valueFromDB("K")
+}