[Cleanup the Polly codebase] Warning CA1062

[Zombach]

Checklist

The issue or feature being addressed

#1290 Cleanup codebase
Namely suppress CA1062 Validate arguments in the code or fix the warning

Details on the issue fix or feature implementation

Since the task is big,
This must be done in several stages.
The first stage is warning suppression.
Then each next PR - processing of one file and adding tests

• Warning Suppression CA1062
• src/Polly/Bulkhead/AsyncBulkheadPolicy.cs
• src/Polly/Bulkhead/BulkheadPolicy.cs
• src/Polly/Caching/AsyncCachePolicy.cs
• src/Polly/Caching/AsyncCacheSyntax.cs
• src/Polly/Caching/AsyncCacheTResultSyntax.cs
• src/Polly/Caching/CachePolicy.cs
• src/Polly/Caching/CacheSyntax.cs
• src/Polly/Caching/CacheTResultSyntax.cs
• src/Polly/Caching/ContextualTtl.cs
• src/Polly/Caching/DefaultCacheKeyStrategy.cs
• src/Polly/CircuitBreaker/AsyncCircuitBreakerPolicy.cs
• src/Polly/CircuitBreaker/CircuitBreakerPolicy.cs
• src/Polly/Fallback/AsyncFallbackPolicy.cs
• src/Polly/Fallback/FallbackPolicy.cs
• src/Polly/NoOp/AsyncNoOpPolicy.cs
• src/Polly/NoOp/NoOpPolicy.cs
• src/Polly/RateLimit/AsyncRateLimitPolicy.cs
• src/Polly/RateLimit/RateLimitPolicy.cs
• src/Polly/Retry/AsyncRetryPolicy.cs
• src/Polly/Retry/RetryPolicy.cs
• src/Polly/Timeout/AsyncTimeoutPolicy.cs
• src/Polly/Timeout/TimeoutPolicy.cs
• src/Polly/Wrap/IAsyncPolicyPolicyWrapExtensions.cs
• src/Polly/Wrap/IPolicyWrapExtension.cs
• src/Polly/Wrap/ISyncPolicyPolicyWrapExtensions.cs

Warning suppression must be removed for each file
#pragma warning disable CA1062 // Validate arguments of public methods
Next, make changes to the code, checking for null for the necessary arguments.
Next, add tests, if necessary.

[Zombach]

@martincostello Thanks for the prompt review