Opening CAS editor sometimes fails

**Describe the bug**
Opening a CAS (XMI or BCAS - does not matter) in the CAS editor sometimes fails with an exception.

**To Reproduce**
Steps to reproduce the behavior - works sometimes, sometimes not...
1. Open Eclipse
2. Copy an XMI file into a project
3. Copy a type system file into the project, but do not name it `TypeSystem.xml`
4. Open the XMI
5. From the open editor select to load the CAS using the type system file
6. Poof

**Expected behavior**
CAS should open.

**Screenshots**

**With XMI**
```
ava.lang.NullPointerException: Cannot load from object array because "this.svd.generators" is null
at org.apache.uima.cas.impl.CASImpl.createFSAnnotCheck(CASImpl.java:1473)
at org.apache.uima.cas.impl.CASImpl.createFS(CASImpl.java:1455)
at org.apache.uima.cas.impl.XmiCasDeserializer$XmiCasDeserializerHandler.readFS(XmiCasDeserializer.java:614)
at org.apache.uima.cas.impl.XmiCasDeserializer$XmiCasDeserializerHandler.processDeferredFSs(XmiCasDeserializer.java:2096)
at org.apache.uima.cas.impl.XmiCasDeserializer$XmiCasDeserializerHandler.readFS(XmiCasDeserializer.java:514)
at org.apache.uima.cas.impl.XmiCasDeserializer$XmiCasDeserializerHandler.startElement(XmiCasDeserializer.java:440)
at org.apache.uima.util.XmlCasDeserializer$XmlCasDeserializerHandler.startElement(XmlCasDeserializer.java:149)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:518)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:183)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:351)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2726)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:112)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:542)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:889)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:825)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1224)
at org.apache.uima.util.XmlCasDeserializer.deserializeR(XmlCasDeserializer.java:109)
at org.apache.uima.util.CasIOUtils.load(CasIOUtils.java:439)
at org.apache.uima.util.CasIOUtils.load(CasIOUtils.java:380)
at org.apache.uima.util.CasIOUtils.load(CasIOUtils.java:242)
at org.apache.uima.util.CasIOUtils.load(CasIOUtils.java:265)
at org.apache.uima.caseditor.editor.DocumentUimaImpl.setContent(DocumentUimaImpl.java:306)
at org.apache.uima.caseditor.editor.DocumentUimaImpl.(DocumentUimaImpl.java:108)
at org.apache.uima.caseditor.ide.DefaultCasDocumentProvider.createDocument(DefaultCasDocumentProvider.java:395)
at org.apache.uima.caseditor.editor.TextDocumentProvider.createDocument(TextDocumentProvider.java:105)
at org.eclipse.ui.texteditor.AbstractDocumentProvider.createElementInfo(AbstractDocumentProvider.java:330)
at org.apache.uima.caseditor.editor.TextDocumentProvider.createElementInfo(TextDocumentProvider.java:137)
at org.eclipse.ui.texteditor.AbstractDocumentProvider.connect(AbstractDocumentProvider.java:395)
at org.eclipse.ui.texteditor.AbstractTextEditor.doSetInput(AbstractTextEditor.java:4177)
at org.eclipse.ui.texteditor.StatusTextEditor.doSetInput(StatusTextEditor.java:262)
at org.apache.uima.caseditor.editor.AnnotationEditor.doSetInput(AnnotationEditor.java:934)
at org.eclipse.ui.texteditor.AbstractTextEditor.setInputWithNotify(AbstractTextEditor.java:4238)
at org.eclipse.ui.texteditor.AbstractTextEditor.setInput(AbstractTextEditor.java:4258)
at org.apache.uima.caseditor.editor.AnnotationEditor.reopenEditorWithNewTypeSystem(AnnotationEditor.java:1178)
at org.apache.uima.caseditor.ide.DefaultCasDocumentProvider$1.widgetSelected(DefaultCasDocumentProvider.java:551)
```

**With BCAS**
```
java.lang.NullPointerException: Cannot load from object array because "this.svd.generators" is null
at org.apache.uima.cas.impl.CASImpl.createFSAnnotCheck(CASImpl.java:1473)
at org.apache.uima.cas.impl.CASImpl.createFS(CASImpl.java:1455)
at org.apache.uima.cas.impl.BinaryCasSerDes6.createCurrentFs(BinaryCasSerDes6.java:2130)
at org.apache.uima.cas.impl.BinaryCasSerDes6.deserializeAfterVersion(BinaryCasSerDes6.java:2075)
at org.apache.uima.cas.impl.BinaryCasSerDes.reinit(BinaryCasSerDes.java:586)
at org.apache.uima.util.CasIOUtils.load(CasIOUtils.java:454)
at org.apache.uima.util.CasIOUtils.load(CasIOUtils.java:380)
at org.apache.uima.util.CasIOUtils.load(CasIOUtils.java:242)
at org.apache.uima.util.CasIOUtils.load(CasIOUtils.java:265)
at org.apache.uima.caseditor.editor.DocumentUimaImpl.setContent(DocumentUimaImpl.java:306)
at org.apache.uima.caseditor.editor.DocumentUimaImpl.(DocumentUimaImpl.java:108)
at org.apache.uima.caseditor.ide.DefaultCasDocumentProvider.createDocument(DefaultCasDocumentProvider.java:395)
at org.apache.uima.caseditor.editor.TextDocumentProvider.createDocument(TextDocumentProvider.java:105)
at org.eclipse.ui.texteditor.AbstractDocumentProvider.createElementInfo(AbstractDocumentProvider.java:330)
at org.apache.uima.caseditor.editor.TextDocumentProvider.createElementInfo(TextDocumentProvider.java:137)
at org.eclipse.ui.texteditor.AbstractDocumentProvider.connect(AbstractDocumentProvider.java:395)
at org.eclipse.ui.texteditor.AbstractTextEditor.doSetInput(AbstractTextEditor.java:4177)
at org.eclipse.ui.texteditor.StatusTextEditor.doSetInput(StatusTextEditor.java:262)
at org.apache.uima.caseditor.editor.AnnotationEditor.doSetInput(AnnotationEditor.java:934)
at org.eclipse.ui.texteditor.AbstractTextEditor.setInputWithNotify(AbstractTextEditor.java:4238)
at org.eclipse.ui.texteditor.AbstractTextEditor.setInput(AbstractTextEditor.java:4258)
at org.apache.uima.caseditor.editor.AnnotationEditor.reopenEditorWithNewTypeSystem(AnnotationEditor.java:1178)
at org.apache.uima.caseditor.ide.DefaultCasDocumentProvider$1.widgetSelected(DefaultCasDocumentProvider.java:551)
```

**Please complete the following information:**
- Version: 3.5.0-SNAPSHOT
- OS: OS X