[Tests] Trim contents before checking for FIR_IDENTICAL

compiler/testData/diagnostics/tests/inference/capturedTypes/approximateBeforeFixation.fir.kt

@@ -1,8 +0,0 @@
-
-fun <T> Array<out T>.intersect(other: Iterable<T>) {
-    val set = toMutableSet()
-    set.retainAll(other)
-}
-
-fun <X> Array<out X>.toMutableSet(): MutableSet<X> = TODO()
-fun <Y> MutableCollection<in Y>.retainAll(elements: Iterable<Y>) {}

compiler/testData/diagnostics/tests/inference/capturedTypes/approximateBeforeFixation.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 fun <T> Array<out T>.intersect(other: Iterable<T>) {
     val set = toMutableSet()
     set.retainAll(other)

compiler/testData/diagnostics/tests/inference/fixVariableToNothing.fir.kt

@@ -1,15 +0,0 @@
-
-// completion order here: X, Y, WHEN_VARIABLE
-fun <T> List<T>.optimizeReadOnlyList() = when (size) {
-    0 -> emptyList() // here type variable Y will be fixed to Nothing
-    1 -> listOf(this[0])
-    else -> this
-}
-fun <X> listOf(element: X): List<X> = TODO()
-fun <Y> emptyList(): List<Y> = TODO()
-
-
-fun test(l: List<String>): List<String> {
-    val foo = l.optimizeReadOnlyList()
-    return foo
-}

compiler/testData/diagnostics/tests/inference/fixVariableToNothing.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // completion order here: X, Y, WHEN_VARIABLE
 fun <T> List<T>.optimizeReadOnlyList() = when (size) {
     0 -> emptyList() // here type variable Y will be fixed to Nothing