add lost tests

compiler/testData/readClass/type/ArrayOfCharSequence.kt

@@ -0,0 +1,3 @@
+package test
+
+fun nothing(): Array<java.lang.CharSequence> = throw Exception()

compiler/testData/writeSignature/Int.kt

@@ -0,0 +1,6 @@
+fun key(): Int = throw Exception()
+
+// method: namespace::key
+// jvm signature:     ()I
+// generic signature: null
+// kotlin signature:  ()I // TODO: make null

compiler/testData/writeSignature/IntQ.kt

@@ -0,0 +1,6 @@
+fun sometimes(): Int? = null
+
+// method: namespace::sometimes
+// jvm signature:     ()Ljava/lang/Integer;
+// generic signature: null
+// kotlin signature:  ()?Ljava/lang/Integer; // TODO: need to skip kotlin signature