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/MapExample.kt

@@ -0,0 +1,3 @@
+package test
+
+class MapImpl<V> : MapExample<String, V>(), MutableMap<String, V>