Test failure: System.Net.Security.Tests.NegotiateAuthenticationKerberosTest.ChannelBindings_Matching_Unique_Succeeds

**Failed in:** [runtime-coreclr libraries-pgo 20260830.1](https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1574201)

**Failed tests:**
```
net11.0-linux-Release-arm-fullpgo_random_gdv-(Debian.13.Arm32.Open)AzureLinux.3.Arm64.Open@mcr.microsoft.com/dotnet-buildtools/prereqs:debian-13-helix-arm32v7@sha256:2ac4e961986424981bcbeb590b61c6db413bf7565d310c5e7ab13dfbedb2ee9d
- System.Net.Security.Tests.NegotiateAuthenticationKerberosTest.ChannelBindings_Matching_Unique_Succeeds

```

**Error message:**
```
Microsoft.DotNet.RemoteExecutor.RemoteExecutionException : Remote process failed with an unhandled exception.
```

**Stack trace:**
```
Child exception:
Xunit.Sdk.EqualException: Assert.Equal() Failure: Values differ
Expected: Completed
Actual: UnknownCredentials
at System.Net.Security.Tests.NegotiateAuthenticationKerberosTest.RunMatching(ChannelBindingKind kind) in /_/src/libraries/System.Net.Security/tests/FunctionalTests/NegotiateAuthenticationKerberosTest.ChannelBindings.cs:line 77
at System.Net.Security.Tests.NegotiateAuthenticationKerberosTest.<>c.b__9_1() in /_/src/libraries/System.Net.Security/tests/FunctionalTests/NegotiateAuthenticationKerberosTest.ChannelBindings.cs:line 38
at System.RuntimeMethodHandle.InvokeMethod(ObjectHandleOnStack target, Void** arguments, ObjectHandleOnStack sig, BOOL isConstructor, ObjectHandleOnStack result)
at System.RuntimeMethodHandle.InvokeMethod(ObjectHandleOnStack target, Void** arguments, ObjectHandleOnStack sig, BOOL isConstructor, ObjectHandleOnStack result)
at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor) in /_/src/coreclr/System.Private.CoreLib/src/System/RuntimeHandles.cs:line 1187
at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args) in /_/src/coreclr/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.CoreCLR.cs:line 37
at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr) in /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs:line 57

Child process:
System.Net.Security.Tests, Version=11.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51 System.Net.Security.Tests.NegotiateAuthenticationKerberosTest+<>c Void b__9_1()
```

Start with System.Net.Security/tests/FunctionalTests/NegotiateAuthenticationKerberosTest.ChannelBindings.cs, especially RunMatching at line 77 and RunMatchingTest at line 38. Reproduce the failure in the listed Debian 13 Arm32 full-PGO environment and compare the UnknownCredentials result with the expected Completed status. Done means the test no longer fails in that environment.

Written by the indexing model from the issue text.