Optimize analyzer hot paths and metadata lookups

[meziantou]

Why

Analyzer callbacks run on every compilation and frequently during editing. Several hot paths were doing repeated LINQ enumerations, per-callback metadata type resolution, and repeated regex/config string work, creating avoidable CPU and allocation overhead.

What changed

• Optimized shared internals used by many analyzers:
  • MethodSymbolExtensions: replaced Any()/First() on explicit interface implementations with direct Length/index access.
  • ContextExtensions: removed multiple re-enumerations of source locations when reporting diagnostics.
  • TypeSymbolExtensions: replaced LINQ predicate-based checks with loop-based implementations for interface and attribute lookups.
• Updated OptimizeLinqUsageAnalyzer to reduce diagnostic-property allocations by using dictionary builders and helper creators, and replaced Replace("OrderBy", "ThenBy") with explicit method-name mapping.
• Updated NamedParameterAnalyzer to cache config keys as static fields and cache compiled regex instances per compilation-start context.
• Hoisted repeated GetBestTypeByMetadataName lookups out of hot callbacks into compilation start for targeted analyzers (naming/design/usage/perf rules touched in this branch).

Notes for reviewers

These are intended as behavior-preserving perf refactors. The changes focus on reducing hot-path allocations and repeated metadata lookups without changing diagnostics semantics.

Validation

• dotnet build
• dotnet test tests/Meziantou.Analyzer.Test/Meziantou.Analyzer.Test.csproj
• dotnet test tests/Meziantou.Analyzer.Test/Meziantou.Analyzer.Test.csproj /p:RoslynVersion=roslyn4.2 --filter 'FullyQualifiedName~AddOverloadWithSpanOrMemoryAnalyzerTests|FullyQualifiedName~AttributeNameShouldEndWithAttributeAnalyzerTests|FullyQualifiedName~AvoidLockingOnPubliclyAccessibleInstanceAnalyzerTests|FullyQualifiedName~DoNotUseEqualityComparerDefaultOfStringAnalyzerTests|FullyQualifiedName~DontTagInstanceFieldsWithThreadStaticAttributeAnalyzerTests|FullyQualifiedName~EventArgsNameShouldEndWithEventArgsAnalyzerTests|FullyQualifiedName~EventsShouldHaveProperArgumentsAnalyzerTests|FullyQualifiedName~ExceptionNameShouldEndWithExceptionAnalyzerTests|FullyQualifiedName~MarkAttributesWithAttributeUsageAttribute|FullyQualifiedName~NamedParameterAnalyzerTests|FullyQualifiedName~NonFlagsEnumsShouldNotBeMarkedWithFlagsAttributeAnalyzerTests|FullyQualifiedName~OptimizeLinqUsageAnalyzer'
• dotnet run --project src/DocumentationGenerator

A full Roslyn 4.2 run in this environment still reports one unrelated existing failure (DoNotNaNInComparisonsAnalyzerTests.Comparisons_CodeFix_Half, NullReferenceException).