Add more tests for ResponseEntity handling

integration-tests/spring-web/src/main/java/io/quarkus/it/spring/web/ExceptionThrowingController.java

@@ -1,5 +1,6 @@
 package io.quarkus.it.spring.web;
 
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
@@ -39,4 +40,9 @@ public Greeting greetingWithIllegalArgumentException() {
         throw new IllegalArgumentException("hello from error");
     }
 
+    @GetMapping("/re")
+    public ResponseEntity<Greeting> responseEntityWithIllegalArgumentException() {
+        throw new IllegalStateException("hello from error");
+    }
+
 }

integration-tests/spring-web/src/test/java/io/quarkus/it/spring/web/SpringControllerTest.java

@@ -98,4 +98,12 @@ public void testRestControllerWithoutRequestMapping() {
         RestAssured.when().get("/hello").then()
                 .body(containsString("hello"));
     }
+
+    @Test
+    public void testResponseEntityWithIllegalArgumentException() {
+        RestAssured.when().get("/exception/re").then()
+                .contentType("application/json")
+                .body(containsString("hello from error"))
+                .statusCode(402);
+    }
 }