o.a.s.common.rest.codec.RestCodec的解析请求参数异常的错误信息不合理

从 RestCodec.java 中的 RestCodec.restToArgs 开始，按照 stack trace 所示，跟踪参数处理流程直到 FormProcessorCreator$PartProcessor.getValue。检查请求解析异常如何变成记录的错误，并找出相关测试或错误处理路径。完成的标准是：报告的错误能够清楚地描述请求参数失败。

15:15:01 ERROR [group0-1-thread-1] o.a.s.common.rest.codec.RestCodec 73 -> Parameter is not valid for operation [bids_service.bidsImportRestService.importRestBIDS]. Parameter is [packageFile]. Processor is [formData].
java.lang.IllegalStateException: getReader() has already been called for this request
at org.apache.catalina.connector.Request.getInputStream(Request.java:1053)
at org.apache.tomcat.util.http.fileupload.servlet.ServletRequestContext.getInputStream(ServletRequestContext.java:102)
at org.apache.tomcat.util.http.fileupload.impl.FileItemIteratorImpl.init(FileItemIteratorImpl.java:178)
at org.apache.tomcat.util.http.fileupload.impl.FileItemIteratorImpl.getMultiPartStream(FileItemIteratorImpl.java:205)
at org.apache.tomcat.util.http.fileupload.impl.FileItemIteratorImpl.findNextItem(FileItemIteratorImpl.java:224)
at org.apache.tomcat.util.http.fileupload.impl.FileItemIteratorImpl.(FileItemIteratorImpl.java:142)
at org.apache.tomcat.util.http.fileupload.FileUploadBase.getItemIterator(FileUploadBase.java:277)
at org.apache.tomcat.util.http.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:301)
at org.apache.catalina.connector.Request.parseParts(Request.java:2849)
at org.apache.catalina.connector.Request.getParts(Request.java:2750)
at org.apache.catalina.connector.Request.getPart(Request.java:2916)
at org.apache.catalina.connector.RequestFacade.getPart(RequestFacade.java:803)
at javax.servlet.http.HttpServletRequestWrapper.getPart(HttpServletRequestWrapper.java:339)
at javax.servlet.http.HttpServletRequestWrapper.getPart(HttpServletRequestWrapper.java:339)
at org.apache.servicecomb.common.rest.codec.param.FormProcessorCreator$PartProcessor.getValue(FormProcessorCreator.java:185)
at org.apache.servicecomb.common.rest.codec.RestCodec.restToArgs(RestCodec.java:63)
at org.apache.servicecomb.common.rest.filter.inner.ServerRestArgsFilter.afterReceiveRequest(ServerRestArgsFilter.java:62)
at org.apache.servicecomb.common.rest.AbstractRestInvocation.prepareInvoke(AbstractRestInvocation.java:239)
at org.apache.servicecomb.common.rest.AbstractRestInvocation.invoke(AbstractRestInvocation.java:216)
at org.apache.servicecomb.common.rest.AbstractRestInvocation.runOnExecutor(AbstractRestInvocation.java:206)
at org.apache.servicecomb.common.rest.AbstractRestInvocation.lambda$scheduleInvocation$0(AbstractRestInvocation.java:162)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:750)