THRIFT-5823 Fix illegal uses of exceptions as normal struct type
Patch: Jens Geyer

This closes #1928
diff --git a/lib/netstd/Tests/Thrift.Compile.Tests/Thrift5320.exception.thrift b/lib/netstd/Tests/Thrift.Compile.Tests/Thrift5320.exception.thrift
index 37421c0..d61a300 100644
--- a/lib/netstd/Tests/Thrift.Compile.Tests/Thrift5320.exception.thrift
+++ b/lib/netstd/Tests/Thrift.Compile.Tests/Thrift5320.exception.thrift
@@ -24,7 +24,10 @@
 
 
 exception Task { 
-	1: Task left 
-	2: Task right 
+	1: ErrorData data  // it would be illegal to use exception as struct type
+}
+
+struct ErrorData {
+	1: string messitsch
 }