[JS IR] Improve debug info precision for blocks

Namely:
- Generate debug info for closing braces, which allows the breakpoints
  set on closing braces to be hit
- Generate debug info for 'if' and 'try/catch' statements.

KT-46276

compiler/testData/debug/stepping/whenMultiLine.kt

@@ -92,3 +92,4 @@ fun box() {
 // test.kt:28 box
 // test.kt:19 foo
 // test.kt:22 foo
+// test.kt:29 box