Fix various small issues with the orchestrator (#2736)

## Motivation and Context
<!--- Why is this change required? What problem does it solve? -->
<!--- If it fixes an open issue, please link to the issue here -->
This change fixes many of the smaller issues I ran into during the
implementation of standard retries for the orchestrator. Merges from
`main` were getting difficult with my [other
PR](https://github.com/awslabs/smithy-rs/pull/2725) so I'm breaking
things up.

## Description
<!--- Describe your changes in detail -->
- when orchestrator attempt timeout occurs, error is now set in context
- update test connection to allow defining connection events with
optional latency simulation update orchestrator attempt loop to track
iteration count
- set request attempts from the attempt loop
- add comment explaining "rewind" step of making request attempts add
`doesnt_matter` method to `TypeErasedBox`, useful when testing update
tests to use the new `TypeErasedBox::doesnt_matter` method
- add more doc comments
- add `set_subsec_nanos` method to `DateTime`.
- I added this to make it easier to string-format a datetime that didn't
include the nanos.
- fix Invocation ID interceptor not inserting the expected header update
input type for `OperationError::other` to be more user-friendly
- add `test-util` feature to `aws-smithy-runtime-api`
- add `test-util` feature to `aws-runtime`
- fix presigining inlineable to pull in tower dep during codegen

## Testing
<!--- Please describe in detail how you tested your changes -->
<!--- Include details of your testing environment, and the tests you ran
to -->
<!--- see how your change affects other areas of the code, etc. -->
tests have been updated where necessary
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