[FE Test] Rename nested directory in testdata into nestedClasses

This is needed to avoid clash between generated test class `Nested` and
  `@Nested` annotation from JUnit 5

compiler/testData/loadJava/compiledKotlin/nestedClasses/membersReferenceOuterTP.txt

@@ -0,0 +1,15 @@
+package test
+
+public final class MembersReferenceOuterTP</*0*/ P> {
+    /*primary*/ public constructor MembersReferenceOuterTP</*0*/ P>()
+
+    public final inner class Inner /*captured type parameters: /*0*/ P*/ {
+        /*primary*/ public constructor Inner()
+        public final val v: P
+            public final fun `<get-v>`(): P
+        public final val </*0*/ Q : P> Q.w: Q
+            public final fun Q.`<get-w>`(): Q
+        public final fun </*0*/ Q : P> f(): kotlin.Unit
+        public final fun g(/*0*/ p: P): P
+    }
+}