Big change in quickfix tests: no stupid test data format with "before" and "after" file prefixes

idea/testData/quickfix/suppress/forStatement/postfixPlusPlus.kt

@@ -0,0 +1,10 @@
+// "Suppress 'REDUNDANT_NULLABLE' for statement " "true"
+
+fun foo() {
+    var v = Box<String?>()
+    (v: Box<String?<caret>?>)++
+}
+
+class Box<T> {
+    fun inc() = this
+}