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/Int.kt

@@ -1,3 +1,3 @@
 package test
 
-fun lll(a: Int) = a
+fun lll(a: kotlin.Int) = a