Refactor OverrideImplementWithLibTest

Use JdkAndMockLibraryProjectDescriptor instead of a jar file, which needs to be
regenerated every time binary format changes

idea/testData/codeInsight/overrideImplement/withLib/fakeOverrideSrc/dependency.kt

@@ -0,0 +1,5 @@
+package dependency
+
+public open class A {
+    public open fun foo() {}
+}