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/Nesting.java

@@ -0,0 +1,26 @@
+package test;
+
+public class Nesting {
+
+    public test.Nesting.Second.Third.FourthImpl getImpl() { return null; }
+
+    public static final class Second {
+
+        public static final class Third {
+
+            public interface Fourth {
+                public boolean isImplemented();
+            }
+
+            public static final class FourthImpl implements Fourth {
+
+                @Override
+                public boolean isImplemented() { return true; }
+
+            }
+
+        }
+
+    }
+
+}