Specialize Comparable#compareTo for boxed primitives

Support Comparable#compareTo for boxed primitive in redundant
boxing/unboxing analysis, along with CHECKCAST to java.lang.Comparable.

Note that we can do that for Float and Double, too, because
Float#compareTo(Float) and Double#compareTo(Double) are delegated to
Float#compare(float, float) and Double#compare(double, double),
respectively.

Fuse specialized comparison for integers with conditional jumps
if possible (both for Comparable#compareTo and Intrinsics#areEqual).

 #KT-11959 Fixed

compiler/testData/codegen/box/boxingOptimization/intCompareTo.kt

@@ -0,0 +1,8 @@
+fun box(): String {
+    val a: Any = 1
+    val b: Any = 42
+    val test = (a as Comparable<Any>).compareTo(b)
+    if (test != -1) return "Fail: $test"
+
+    return "OK"
+}