Avoid ArgumentException thrown for invalid file path in CodeAnalysisTargets

eng/targets/Settings.props

@@ -30,7 +30,7 @@
     <UseRoslynAnalyzers Condition="'$(UseRoslynAnalyzers)' == ''">true</UseRoslynAnalyzers>
 
     <!-- Set to non-existent file to prevent common targets from importing Microsoft.CodeAnalysis.targets -->
-    <CodeAnalysisTargets>*none*</CodeAnalysisTargets>
+    <CodeAnalysisTargets>NON_EXISTENT_FILE</CodeAnalysisTargets>
 
     <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">15.0</VisualStudioVersion>
     <VisualStudioReferenceMajorVersion Condition="'$(VisualStudioReferenceMajorVersion)' == ''">$(VisualStudioVersion.Substring($([System.Convert]::ToInt32(0)), $(VisualStudioVersion.IndexOf('.'))))</VisualStudioReferenceMajorVersion>