Implement FIR loading for Java (classes, supertypes, parameters, funs)

Properties aren't implemented yet
FIR symbol provider functions return more specialized types now
Related to KT-28918, KT-29636, KT-29218

#KT-28788 Fixed

idea/testData/fir/multiModule/overrideWithJava/jvm/B.kt

@@ -0,0 +1,9 @@
+class B : A() {
+    override fun foo(): B = this
+    fun bar(): B = this // Ambiguity, no override here
+
+    fun test() {
+        foo()
+        bar()
+    }
+}