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/Inheritance.java

@@ -0,0 +1,25 @@
+package test;
+
+public class Inheritance extends AbstractInheritance { }
+
+abstract class AbstractInheritance implements Interface {
+
+    @Override public int getAnswer() { return 42; }
+
+}
+
+interface Interface extends I {
+    @Override
+    int getAnswer();
+}
+
+interface I {
+    int getAnswer();
+}
+
+interface I2 extends I {
+
+    @Override
+    int getAnswer();
+
+}