[JVM+IR] Unify new debugger tests expectations

This commit unifies the expectation format between the stepping and
LVT tests in the new debugging test harness.

Furthermore, it introduces a compression of runs of locations without
linenumbers. These default to showing as bytecode offsets from
previous line number, which overspecifies the tests: the bytecodes
chosen should not be constrained by a debugging step test.

compiler/testData/debug/localVariables/receiverParameter.kt

@@ -8,6 +8,6 @@ fun box() {
 }
 
 // LOCAL VARIABLES
-// TestKt:7:
-// TestKt:4: $this$test:java.lang.String="OK":java.lang.String
-// TestKt:8:
+// test.kt:7 box:
+// test.kt:4 test: $this$test:java.lang.String="OK":java.lang.String
+// test.kt:8 box: