SystemTrustCertificateWithCustomRootTrust fails on macOS 26

[vcsjones]

This test started failing on macOS 26 beta 6. All theories.

Failed System.Security.Cryptography.X509Certificates.Tests.ChainTests.SystemTrustCertificateWithCustomRootTrust(addCertificateToCustomRootTrust: True) [127 ms]
  Error Message:
   Assert.Equal() Failure: Values differ
Expected: 3
Actual:   2
  Stack Trace:
     at System.Security.Cryptography.X509Certificates.Tests.ChainTests.SystemTrustCertificateWithCustomRootTrust(Boolean addCertificateToCustomRootTrust) in /Users/vcsjones/Projects/runtime/src/libraries/System.Security.Cryptography/tests/X509Certificates/ChainTests.cs:line 293
   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.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr) in /Users/vcsjones/Projects/runtime/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs:line 174

  Failed System.Security.Cryptography.X509Certificates.Tests.ChainTests.SystemTrustCertificateWithCustomRootTrust(addCertificateToCustomRootTrust: False) [102 ms]
  Error Message:
   Assert.Equal() Failure: Values differ
Expected: 3
Actual:   2
  Stack Trace:
     at System.Security.Cryptography.X509Certificates.Tests.ChainTests.SystemTrustCertificateWithCustomRootTrust(Boolean addCertificateToCustomRootTrust) in /Users/vcsjones/Projects/runtime/src/libraries/System.Security.Cryptography/tests/X509Certificates/ChainTests.cs:line 293
   at InvokeStub_ChainTests.SystemTrustCertificateWithCustomRootTrust(Object, Span`1)
   at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) in /Users/vcsjones/Projects/runtime/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs:line 95

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[vcsjones]

Fixed by #118652.