JVM_IR don't inline temporary val for 'when' subject

compiler/testData/debug/stepping/whenConstant.kt

@@ -12,14 +12,9 @@ fun box() {
 }
 
 // JVM_IR and JVM backends have different heuristics for when to use a switch.
-// JVM_IR does not use a switch in this case and therefore steps to the evaluation
-// of the condition for each of the cases.
+// JVM_IR inlines constant value subject and folds unreachable branches.
 
 // LINENUMBERS
 // test.kt:4 box
-// LINENUMBERS JVM_IR
-// test.kt:5 box
-// test.kt:7 box
-// LINENUMBERS
 // test.kt:10 box
 // test.kt:12 box