Add a test for KT-54318

compiler/testData/codegen/box/casts/kt54318.kt

@@ -0,0 +1,19 @@
+// TARGET_BACKEND: JVM_IR
+
+fun f(b: Int): Long? {
+    return try {
+        null
+    } catch (e: Throwable) {
+        if (b == 0)
+            throw e
+        else {
+            null
+        }
+    }
+}
+
+fun box(): String {
+    f(0)
+    f(1)
+    return "OK"
+}