Defensively ignore multipart parsing failure in case of error dispatch

Issue: SPR-15231
(cherry picked from commit d44325e)

Author: jhoeller

spring-webmvc/src/main/java/org/springframework/web/servlet/DispatcherServlet.java

@@ -1096,7 +1096,18 @@ else if (hasMultipartException(request) ) {
 						"skipping re-resolution for undisturbed error rendering");
 			}
 			else {
-				return this.multipartResolver.resolveMultipart(request);
+				try {
+					return this.multipartResolver.resolveMultipart(request);
+				}
+				catch (MultipartException ex) {
+					if (request.getAttribute(WebUtils.ERROR_EXCEPTION_ATTRIBUTE) != null) {
+						logger.debug("Multipart resolution failed for error dispatch", ex);
+						// Keep processing error dispatch with regular request handle below
+					}
+					else {
+						throw ex;
+					}
+				}
 			}
 		}
 		// If not returned before: return original request.