FIR UAST: fix/test allCommentsInFile in UFile

plugins/uast-kotlin-fir/testData/declaration/facade.comments.txt

@@ -0,0 +1,6 @@
+UFile(allCommentsInFile:
+UComment(// Single-line comment bound to fun foo)
+UComment(/*
+ * Multi-line comment bound to extension fun buzz
+ */)
+)

plugins/uast-kotlin-fir/testData/declaration/facade.kt

@@ -3,8 +3,12 @@
 
 package declaration
 
+// Single-line comment bound to fun foo
 fun foo(): Int = 42
 
+/*
+ * Multi-line comment bound to extension fun buzz
+ */
 fun String.buzz(): String {
     return "$this... zzz..."
 }

plugins/uast-kotlin-fir/testData/declaration/objects.comments.txt

@@ -0,0 +1,5 @@
+UFile(allCommentsInFile:
+UComment(// file comment)
+UComment(// Single-line comment bound to top-level property)
+UComment(// Single-line comment bound to object)
+)

plugins/uast-kotlin-fir/testData/declaration/objects.kt

@@ -1,12 +1,16 @@
 import java.lang.Runnable
 import java.lang.Thread
 
+// file comment
+
+// Single-line comment bound to top-level property
 val topRunnable = object : Runnable {
     override fun run() {
         println("I'm running")
     }
 }
 
+// Single-line comment bound to object
 object RunnableManager {
     val tasks : MutableList<Runnable> = mutableListOf<Runnable>()