fix: handle types without a namespace or assembly in reside-in checks

[iamAdarshh]

Function pointer types (Cecil FunctionPointerType) are created by DomainResolver with a null Namespace and a null Assembly. They only show up in ReferencedTypes, so Types() rules work, but any namespace/assembly predicate on Types(true) throws a NullReferenceException, as reported in #492:

Types(true).That().ResideInNamespace("System").GetObjects(architecture) // NRE on System.Private.CoreLib

This follows Option 1 from the issue, as the maintainer suggested: null-guard the helpers instead of dropping function pointers from the type set.

Changes

• TypeExtensions: ResidesInNamespace, ResidesInNamespaceMatching, ResidesInAssembly and ResidesInAssemblyMatching return false for a type without a namespace/assembly.
• TypeConditionsDefinition:
  • SimpleCondition builds the failure description eagerly, even for passing objects, so every ResideIn*/NotResideIn* condition dereferenced Namespace.FullName/Assembly.FullName. Those messages now go through two helpers (ResideInNamespaceFailDescription / ResideInAssemblyFailDescription) that fall back to "does not reside in a namespace" / "does not reside in an assembly".
  • The System.Reflection.Assembly overloads of ResideInAssembly/NotResideInAssembly compared with ruleType.Assembly.Equals(...). They now use the static Equals(a, b).
• Tests: a new TestAssemblies/FunctionPointerAssembly contains a class with a delegate*<int, void> field and is loaded as its own FunctionPointerArchitecture. FunctionPointerTests covers the extension methods, the predicates (ResideIn*/DoNotResideIn*) and the conditions for both namespace and assembly. All of them failed with an NRE before this change.

I also ran the exact snippet from the issue against System.Private.CoreLib. The 32 null-namespace referenced types are still present, and Types(true).That().ResideInNamespace("System") now returns results instead of throwing.

The issue only mentions the namespace helpers. I included the assembly side because function pointers have a null Assembly too, and ResideInAssembly on Types(true) fails the same way. If you'd rather keep this PR to the namespace fix, I'm happy to split it out.

dotnet build, dotnet test and mise run check pass locally.

Resolves #492

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.51%. Comparing base (d47d6a0) to head (4f4d3bb).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #501      +/-   ##
==========================================
+ Coverage   86.46%   86.51%   +0.04%     
==========================================
  Files         261      261              
  Lines       12600    12610      +10     
  Branches     1227     1233       +6     
==========================================
+ Hits        10895    10909      +14     
+ Misses       1366     1359       -7     
- Partials      339      342       +3     

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[alexanderlinne]

Hi @iamAdarshh, I've tried to resolve the conflicts manually but the formatting was not quite correct. Could you please fix that on your branch, ideally properly rebase the branch onto the current main