Support nested classes in KotlinCliJavaFileManagerImpl.findClass

findClass(String, GlobalSearchScope) is invoked for example when we're
resolving supertypes of classes in Java libraries. Previously, it never
found nested classes and falled back to CoreJavaFileManager's
implementation, which lacks a fix for the original issue (KT-12664,
which was fixed in JvmDependenciesIndex in 5a533a52 and 164c72e8)

 #KT-16931 Fixed

compiler/testData/compileKotlinAgainstCustomBinaries/innerClassPackageConflict/library/test/Baz.java

@@ -0,0 +1,6 @@
+package test;
+
+public class Baz implements Foo.Bar {
+    @Override
+    public void bar() {}
+}

compiler/testData/compileKotlinAgainstCustomBinaries/innerClassPackageConflict/library/test/Foo.java

@@ -2,6 +2,6 @@ package test;
 
 public class Foo {
     public interface Bar {
-
+        void bar();
     }
 }

compiler/testData/compileKotlinAgainstCustomBinaries/innerClassPackageConflict/source.kt

@@ -1,3 +1,5 @@
 import test.Foo.Bar
+import test.Baz
 
 val f: Bar? = null
+val g: Baz? = Baz().apply { bar() }