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/compileJavaAgainstKotlin/method/IntArray.kt

@@ -1,4 +1,4 @@
 package test
 
 // extra parameter is to make sure generic signature is not erased
-fun doNothing(array: IntArray, ignore: java.util.List<String>) = array
+fun doNothing(array: kotlin.IntArray, ignore: java.util.List<String>) = array