Added cleanup for cached async state in SqlCommand's EndExecute methods before they throw exceptions. Without this cleanup, a subsequent command execution will fail since it will appear as though other async commands are still pending. (#20339) (#20373)

Author: corivera

src/System.Data.SqlClient/src/System/Data/SqlClient/SqlCommand.cs

@@ -1002,6 +1002,10 @@ private int EndExecuteNonQuery(IAsyncResult asyncResult)
             if (asyncException != null)
             {
                 // Leftover exception from the Begin...InternalReadStage
+                if (cachedAsyncState != null)
+                {
+                    cachedAsyncState.ResetAsyncState();
+                }
                 ReliablePutStateObject();
                 throw asyncException.InnerException;
             }
@@ -1266,6 +1270,10 @@ private XmlReader EndExecuteXmlReader(IAsyncResult asyncResult)
             if (asyncException != null)
             {
                 // Leftover exception from the Begin...InternalReadStage
+                if (cachedAsyncState != null)
+                {
+                    cachedAsyncState.ResetAsyncState();
+                }
                 ReliablePutStateObject();
                 throw asyncException.InnerException;
             }
@@ -1396,6 +1404,10 @@ private SqlDataReader EndExecuteReader(IAsyncResult asyncResult)
             if (asyncException != null)
             {
                 // Leftover exception from the Begin...InternalReadStage
+                if (cachedAsyncState != null)
+                {
+                    cachedAsyncState.ResetAsyncState();
+                }
                 ReliablePutStateObject();
                 throw asyncException.InnerException;
             }