WriteSignatureTest for varargs

compiler/testData/writeSignature/VarargCharSequence.kt

@@ -0,0 +1,6 @@
+fun foo(vararg tail: java.lang.CharSequence) = 1
+
+// method: namespace::foo
+// jvm signature:     ([Ljava/lang/CharSequence;)I
+// generic signature: null
+// kotlin signature:  ([Ljava/lang/CharSequence;)I // TODO: need to skip kotlin signature

compiler/testData/writeSignature/VarargGeneric.kt

@@ -0,0 +1,8 @@
+fun <P> foo(vararg tail: P) = 1
+
+// method: namespace::foo
+// jvm signature:     (Ljet/TypeInfo;[Ljava/lang/Object;)I
+// generic signature: <P:Ljava/lang/Object;>(Ljet/TypeInfo;[TP;)I
+// kotlin signature:  <P:?Ljava/lang/Object;>(null[TP;)I
+// TODO: skip kotlin signature
+// TODO: properly serialize typeinfo