Sync TimeProvider and cleanup

[martintmk]

Details on the issue fix or feature implementation

Syncing our TimeProvider with the official one:
https://github.com/dotnet/runtime/blob/main/src/libraries/Common/src/System/TimeProvider.cs

Contributes to #1144

Confirm the following

• I started this PR by branching from the head of the default branch
• I have targeted the PR to merge into the default branch
• I have included unit tests for the issue/feature
• I have successfully run a local build

[codecov]

Codecov Report

Merging #1339 (fd2a4b1) into main (c6d386a) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1339      +/-   ##
==========================================
+ Coverage   83.49%   83.54%   +0.04%     
==========================================
  Files         270      270              
  Lines        6379     6374       -5     
  Branches     1003     1003              
==========================================
- Hits         5326     5325       -1     
+ Misses        844      840       -4     
  Partials      209      209              

Flag	Coverage Δ
linux	83.54% <100.00%> (+0.04%)	⬆️
macos	83.54% <100.00%> (+0.04%)	⬆️
windows	83.54% <100.00%> (+0.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...rc/Polly.Core/Hedging/HedgingResilienceStrategy.cs	100.00% <ø> (ø)
src/Polly.Core/Outcome.TResult.cs	100.00% <ø> (ø)
src/Polly.Core/Retry/RetryResilienceStrategy.cs	100.00% <ø> (ø)
src/Polly.Core/Utils/DefaultPredicates.cs	100.00% <ø> (ø)
src/Polly.Core/Utils/OutcomeResilienceStrategy.cs	100.00% <ø> (ø)
src/Polly.Extensions/Telemetry/EnrichmentUtil.cs	100.00% <ø> (ø)
src/Polly.Extensions/Telemetry/TelemetryOptions.cs	100.00% <ø> (ø)
...xtensions/Telemetry/TelemetryResilienceStrategy.cs	100.00% <ø> (ø)
.../RateLimiterResilienceStrategyBuilderExtensions.cs	100.00% <ø> (ø)
...ircuitBreaker/Controller/CircuitStateController.cs	100.00% <100.00%> (ø)
... and 3 more

... and 3 files with indirect coverage changes