Iniital implementation of synthetic extensions for SAM-adapter functions (non-static only)

compiler/testData/diagnostics/tests/syntheticExtensions/samAdapters/GenericClass.kt

@@ -0,0 +1,15 @@
+// FILE: KotlinFile.kt
+fun foo(javaClass: JavaClass<String>): String {
+    return javaClass.doSomething("", 1) { s: String -> "" }
+}
+
+fun useString(<!UNUSED_PARAMETER!>s<!>: String) {}
+
+// FILE: JavaClass.java
+public class JavaClass<T> {
+    public T doSomething(T t, int anInt, I<T> i) { return t; }
+}
+
+interface I<T> {
+    T doIt(T t);
+}