[Json] Remove unnecessary Debug.Asserts

src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Node/JsonArrayConverter.cs

@@ -31,7 +31,6 @@ public override void Write(Utf8JsonWriter writer, JsonArray? value, JsonSerializ
                 case JsonTokenType.Null:
                     return null;
                 default:
-                    Debug.Assert(false);
                     throw ThrowHelper.GetInvalidOperationException_ExpectedArray(reader.TokenType);
             }
         }

src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Node/JsonObjectConverter.cs

@@ -69,7 +69,6 @@ public override void Write(Utf8JsonWriter writer, JsonObject? value, JsonSeriali
                 case JsonTokenType.Null:
                     return null;
                 default:
-                    Debug.Assert(false);
                     throw ThrowHelper.GetInvalidOperationException_ExpectedObject(reader.TokenType);
             }
         }

src/libraries/System.Text.Json/tests/System.Text.Json.Tests/JsonNode/JsonArrayTests.cs

@@ -889,5 +889,13 @@ public static void RemoveRange_FreshlyDeserialized()
 
             static JsonArray PrepareData() => JsonSerializer.Deserialize<JsonArray>("[1,2,3,4,5]");
         }
+
+        [Theory]
+        [InlineData("42")]
+        [InlineData("{}")]
+        public static void Deserialize_WrongType(string json)
+        {
+            Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<JsonArray>(json));
+        }
     }
 }

src/libraries/System.Text.Json/tests/System.Text.Json.Tests/JsonNode/JsonObjectTests.cs

@@ -1718,5 +1718,13 @@ public static void JsonObject_NestedDuplicatePropertyCaseInsensitiveThrows()
                 () => JsonSerializer.Deserialize<JsonNode>(jsonPayload, options),
                 "An item with the same key has already been added.");
         }
+
+        [Theory]
+        [InlineData("42")]
+        [InlineData("[]")]
+        public static void Deserialize_WrongType(string json)
+        {
+            Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<JsonObject>(json));
+        }
     }
 }