[JVM] Extend stepping tests with <clinit> stepping.

In addition, made the stepping information for constructor calls
consistent across JVM_IR and JVM. For JVM_IR that stepping behavior
is consistent for enum constructor calls in <clinit> for JVM it
is not.

compiler/testData/debug/stepping/initBlocksCompanion.kt

@@ -32,12 +32,19 @@ fun box() {
 
 // JVM backend has extra steps for getX and getS.
 
-// TODO: since these tests operate as step-into, we do not get any steps
-// in the <clinit> for the companion object. Maybe extend the test infrastructure
-// with directives to set break points in order to test this.
-
 // LINENUMBERS
 // test.kt:29 box
+// test.kt:7 <clinit>
+// test.kt:8 <clinit>
+// test.kt:9 <clinit>
+// test.kt:11 <clinit>
+// test.kt:13 <clinit>
+// test.kt:15 <clinit>
+// test.kt:16 <clinit>
+// test.kt:17 <clinit>
+// test.kt:19 <clinit>
+// test.kt:21 <clinit>
+// test.kt:22 <clinit>
 // test.kt:11 getX
 // LINENUMBERS JVM
 // test.kt:11 getX
@@ -49,4 +56,4 @@ fun box() {
 // test.kt:5 getS
 // LINENUMBERS
 // test.kt:30 box
-// test.kt:31 box
+// test.kt:31 box