Introduce experimental -Xuse-javac compilation mode

In this mode, javac AST and Symbol files are used during
Kotlin compilation instead of PSI / binary stuff.
Later, they are reused for Java file compilation.
javac in this mode is integrated into kotlinc.

compiler/testData/compileKotlinAgainstJava/InheritedInner.java

@@ -0,0 +1,17 @@
+package test;
+
+public class InheritedInner {
+
+    public Third.Second getSecond() { return null; }
+
+    public static class First {
+
+        public static class Second {}
+
+    }
+
+    public static class Third extends First {
+
+    } 
+
+}