JVM_IR KT-45446 don't erase captured var if it's dead code

compiler/testData/codegen/box/closures/capturedVarsOptimization/kt45446.kt

@@ -0,0 +1,25 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: EXCEPTIONS_NOT_IMPLEMENTED
+// This test checks that bytecode optimizer doesn't crash on unreachable code.
+
+fun box(): String {
+    try {
+        remove()
+    }
+    catch (e: Exception) {
+        return e.message!!
+    }
+    return "Should fail with exception"
+}
+
+fun remove() {
+    throw Exception("OK")
+    var captured = 0
+    debug {
+        captured = 1
+    }
+}
+
+private fun debug(f: () -> Unit) {
+    f()
+}