Made LibrariesWithSourcesTest possible to be executed with multi-file test library.

idea/testData/libraries/usercode/ClassObject.kt

@@ -4,6 +4,7 @@ fun foo() {
     WithInnerAndObject.foo()
 }
 
+// library.kt
 //public class <1>WithInnerAndObject {
 //    class object {
 //        fun <2>foo() {

idea/testData/libraries/usercode/Enum.kt

@@ -3,4 +3,5 @@ import testData.libraries.*
 val color: Color? = Color.RED
 val rgb = color?.rgb
 
+// library.kt
 //public enum class <1><2>Color(val <3>rgb : Int) {

idea/testData/libraries/usercode/ExtensionFunction.kt

@@ -2,5 +2,6 @@ import testData.libraries.*
 
 val v = 5.filter { it % 2 == 1 }
 
+// library.kt
 //public inline fun <T> T.<1>filter(predicate: (T)-> Boolean) : T? = this
 

idea/testData/libraries/usercode/ExtensionProperty.kt

@@ -5,6 +5,7 @@ fun foo() {
     println(#(1, 2).exProp)
 }
 
+// library.kt
 //public val String.<1>exProp : String
 //get() {
 //    return this

idea/testData/libraries/usercode/GlobalFunction.kt

@@ -7,6 +7,7 @@ fun foo() {
     func()
 }
 
+// library.kt
 //public fun <1><2>func(a : Int, b : String = "55") {
 //}
 //

idea/testData/libraries/usercode/GlobalProperty.kt

@@ -5,6 +5,7 @@ fun foo() {
     println(globalValWithGetter)
 }
 
+// library.kt
 //public val <1>globalVal : #(Int, String) = #(239, "239")
 //
 //public val <2>globalValWithGetter : Long

idea/testData/libraries/usercode/Property.kt

@@ -5,6 +5,7 @@ fun foo(a : ClassWithAbstractAndOpenMembers) {
     println(a.abstractVar)
 }
 
+// library.kt
 //public abstract class <1>ClassWithAbstractAndOpenMembers {
 //    public abstract fun abstractFun()
 //    public open fun openFun() {