Tests: unmute debugging tests for FIR+JVM_IR

The differences between K1 and K2 are pretty unimportant in these tests.

compiler/testData/debug/localVariables/destructuring/assignmentMultiline.kt

@@ -1,5 +1,5 @@
 // WITH_STDLIB
-// IGNORE_BACKEND_K2: JVM_IR
+
 
 // FILE: test.kt
 fun box(): String {
@@ -19,7 +19,9 @@ fun box(): String {
 
 // EXPECTATIONS JVM_IR
 // test.kt:6 box:
+// EXPECTATIONS ClassicFrontend JVM_IR
 // test.kt:15 box: p:kotlin.Pair=kotlin.Pair
+// EXPECTATIONS JVM_IR
 // test.kt:10 box: p:kotlin.Pair=kotlin.Pair
 // test.kt:12 box: p:kotlin.Pair=kotlin.Pair, o:java.lang.String="O":java.lang.String
 // test.kt:17 box: p:kotlin.Pair=kotlin.Pair, o:java.lang.String="O":java.lang.String, k:java.lang.String="K":java.lang.String