[JVM] Improve debug step behavior around lambdas.

- Add tests to clarify problematic behavior
- Avoid line numbers on return instructions of lambdas without explicit returns

compiler/testData/debug/stepping/lambdaStepInlineWithDefaults.kt

@@ -0,0 +1,42 @@
+// IGNORE_BACKEND: JVM_IR
+// FILE: test.kt
+inline fun foo(stringMaker: () -> String = { "OK" }): String {
+    return stringMaker()
+}
+
+inline fun foo2(stringMaker: () -> String = {
+    "OK"
+    // Comment
+}): String {
+    return stringMaker()
+}
+
+fun box(): String {
+    foo()
+    foo2()
+    return "OK"
+}
+
+// The IR Backend does the following:
+// test.kt:15
+// test.kt:3
+// test.kt:4
+// test.kt:3
+// test.kt:3 <---
+// test.kt:16
+// test.kt:7
+// test.kt:11
+// test.kt:8
+// test.kt:7 <---
+// test.kt:17
+
+// LINENUMBERS
+// test.kt:15
+// test.kt:3
+// test.kt:4
+// test.kt:3
+// test.kt:16
+// test.kt:7
+// test.kt:11
+// test.kt:8
+// test.kt:17