[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/suspend/simple.kt

@@ -6,5 +6,5 @@ suspend fun box() {
 }
 
 // LOCAL VARIABLES
-// TestKt:5: $completion:kotlin.coroutines.Continuation=helpers.ResultContinuation
-// TestKt:6: $completion:kotlin.coroutines.Continuation=helpers.ResultContinuation, x:int=1:int
+// test.kt:5 box: $completion:kotlin.coroutines.Continuation=helpers.ResultContinuation
+// test.kt:6 box: $completion:kotlin.coroutines.Continuation=helpers.ResultContinuation, x:int=1:int