Fix new analyzer errors

Author: lewing

src/tasks/Crossgen2Tasks/RunReadyToRunCompiler.cs

@@ -397,7 +397,7 @@ protected override int ExecuteTool(string pathToTool, string responseFileCommand
 
         protected override void LogEventsFromTextOutput(string singleLine, MessageImportance messageImportance)
         {
-            if (!ShowCompilerWarnings && singleLine.IndexOf("warning:", StringComparison.OrdinalIgnoreCase) != -1)
+            if (!ShowCompilerWarnings && singleLine.Contains("warning:", StringComparison.OrdinalIgnoreCase))
             {
                 Log.LogMessage(MessageImportance.Normal, singleLine);
                 WarningsDetected = true;

src/tasks/WorkloadBuildTasks/InstallWorkloadFromArtifacts.cs

@@ -274,7 +274,7 @@ private void UpdateAppRef(string sdkPath, string version)
         private string GetNuGetConfig()
         {
             string contents = File.ReadAllText(TemplateNuGetConfigPath);
-            if (contents.IndexOf(s_nugetInsertionTag, StringComparison.InvariantCultureIgnoreCase) < 0)
+            if (!contents.Contains(s_nugetInsertionTag, StringComparison.InvariantCultureIgnoreCase))
                 throw new LogAsErrorException($"Could not find {s_nugetInsertionTag} in {TemplateNuGetConfigPath}");
 
             return contents.Replace(s_nugetInsertionTag, $@"<add key=""nuget-local"" value=""{LocalNuGetsPath}"" />");
@@ -423,7 +423,7 @@ internal sealed record InstallWorkloadRequest(
             public string Version => Workload.GetMetadata("Version");
             public string TargetPath => Target.GetMetadata("InstallPath");
             public string StampPath => Target.GetMetadata("StampPath");
-            public bool IgnoreErrors => Workload.GetMetadata("IgnoreErrors").ToLowerInvariant() == "true";
+            public bool IgnoreErrors => Workload.GetMetadata("IgnoreErrors").Equals("true", StringComparison.InvariantCultureIgnoreCase);
             public string WorkloadId => Workload.ItemSpec;
 
             public bool Validate(TaskLoggingHelper log)