Fix Span Debugger Display String to correctly show the string contents

[ahsonkhan]

Resolves https://github.com/dotnet/coreclr/issues/16450

Leftover from #26726 (comment)

cc @stephentoub, @khellang, @pakrym, @KrzysztofCwalina

[pakrym]

How does it look in vs for char vs byte?

[khellang]

LGTM, given it looks good in VS, as @pakrym mentioned 👍

[stephentoub]

By default I thought VS rendered most things with ToString(). I could be wrong, but what happens if you remove the DebuggerDisplay attribute entirely?

[pakrym]

This happens (special characters are not escaped)

[ahsonkhan]

If we don't have it, we end up with the issue mentioned here: #26726 (comment)

With this change (i.e., specifying "raw"), we get the expected result.

[stephentoub]

Ah. Thanks.

[ahsonkhan]

How does it look in vs for char vs byte?

[khellang]

What if you try with "\r\b\0" as in the original issue?

[ahsonkhan]

What if you try with "\r\b\0" as in the original issue?

See #27338 (comment)

[ahsonkhan]

System.Net.Requests.Tests failing on Ubuntu.1604.Amd64.Open:Release-x64 with seg fault:

https://mc.dot.net/#/user/ahsonkhan/pr~2Fjenkins~2Fdotnet~2Fcorefx~2Fmaster~2F/test~2Ffunctional~2Fcli~2F/fd25d3cb8fc8054d5cdc118b24e50a0f931782e0/workItem/System.Net.Requests.Tests/wilogs

2018-02-21 22:08:53,266: INFO: proc(54): run_and_log_output: Output:    System.Net.Tests.FtpWebRequestTest.Ftp_AppendFile [SKIP]
2018-02-21 22:08:53,266: INFO: proc(54): run_and_log_output: Output:       Condition(s) not met: \"LocalServerAvailable\"
2018-02-21 22:08:54,630: INFO: proc(54): run_and_log_output: Output: /home/helixbot/dotnetbuild/work/96d5d89c-3b8b-4afb-9beb-f43b108fdc9f/Work/01a7818b-79e2-43b9-9067-47e346b87957/Unzip/RunTests.sh: line 88: 69406 Segmentation fault      (core dumped) $RUNTIME_PATH/dotnet xunit.console.netcore.exe System.Net.Requests.Tests.dll -xml testResults.xml -notrait Benchmark=true -notrait category=nonnetcoreapptests -notrait category=nonlinuxtests -notrait category=OuterLoop -notrait category=failing
2018-02-21 22:08:54,675: INFO: proc(54): run_and_log_output: Output: Dumpling has not been installed yet. Please run "DumplingHelper.py install_dumpling" before collect_dumps.
2018-02-21 22:08:54,679: INFO: proc(54): run_and_log_output: Output: ~/dotnetbuild/work/96d5d89c-3b8b-4afb-9beb-f43b108fdc9f/Work/01a7818b-79e2-43b9-9067-47e346b87957/Unzip
2018-02-21 22:08:54,680: INFO: proc(54): run_and_log_output: Output: ----- end 22:08:54 ----- exit code 139 ----------------------------------------------------------
2018-02-21 22:08:54,682: INFO: proc(54): run_and_log_output: Output: Unable to find executable corerun
2018-02-21 22:08:54,744: INFO: proc(58): run_and_log_output: Exit Code: 139
2018-02-21 22:08:54,745: ERROR: scriptrunner(91): _main: Error: No exception thrown, but XUnit results not created
2018-02-21 22:08:54,745: ERROR: helix_test_execution(83): report_error: Error running xunit None

cc @davidsh, @Priya91, @wfurt, @geoffkizer

[ahsonkhan]

@dotnet-bot test Linux x64 Release Build

[ahsonkhan]

The Tizen build timed out:
https://ci.dot.net/job/dotnet_corefx/job/master/job/tizen_armel_cross_debug_prtest/12381/

Build timed out (after 120 minutes). Marking the build as aborted.
15:26:13 
Build was aborted

cc @dotnet/dnceng, any ideas why?

@dotnet-bot test Tizen armel Debug Build

[Chrisboh]

@ahsonkhan You will need to reach out to the Tizen folks as they are the owners of those legs. I am not sure who specifically that is but @RussKeldorph I believe knows.