LT-22525: Handle missing POS in msa and empty form hvo (#903)

Change-Id: I7bab55c0de2a4d0bc5340da8fa8765137518f84d

Author: AndyBlack

Src/Utilities/pcpatrflex/ToneParsFLExDll/ANABuilder.cs

@@ -208,7 +208,7 @@ private string GetAnaProperties(ParseMorph pMorph)
 				case MoStemMsaTags.kClassId:
 					var stemMsa = msa as IMoStemMsa;
 					sb.Append("RootPOS");
-					sb.Append(stemMsa.PartOfSpeechRA.Hvo);
+					sb.Append((stemMsa.PartOfSpeechRA != null) ? stemMsa.PartOfSpeechRA.Hvo : 0);
 					break;
 				case MoInflAffMsaTags.kClassId:
 					break;

Src/Utilities/pcpatrflex/ToneParsFLExDll/ToneParsInvoker.cs

@@ -826,7 +826,7 @@ out ParseMorph morph
 			//       The LexEntry is a variant form and the (non-zero) index indicates
 			//       which set of LexEntryRefs it is for.
 			ICmObject objForm;
-			if (
+			if (String.IsNullOrEmpty(formHvo) ||
 				!cache.ServiceLocator
 					.GetInstance<ICmObjectRepository>()
 					.TryGetObject(int.Parse(formHvo), out objForm)