Fix retry policy attempts to match server behavior

[Groxx]

What this changes

Apparently we've had an off-by-one error in the test suite for years now, but few noticed.

Due to this mistake, retry policy config like this:

&workflow.RetryPolicy{
  // ...
  MaximumAttempts: 3,
}

would result in up to four calls in tests, but only three in production.

The server has always considered "MaximumAttempts" to be "total number of calls" (going back to at least 2018 iirc, when I checked), so the test suite is simply wrong.
https://github.com/cadence-workflow/cadence/blob/830974dd9e49365bd974d288b21e949c48089216/service/history/execution/retry.go#L47-L51

What this means for users whose tests are now failing

Unfortunately, this means your tests have been misleading you.
Production is unchanged, your tests are just failing because they've been wrong all along, and you'll need to update them.

Sorry about that 🤦

This is especially true when MaximumAttempts: 1 is configured: this actually means zero retries, not one retry.
Ideally we would disallow MaximumAttempts: 1 because it's so misleading... but this would affect production, so we've been holding off on it. It may change in a later version with more communication though.

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making the CI job happy:

Detailed Description
bugfix, covered above

Impact Analysis

• only affects tests
• no cross-version compatibility at all, it's intentionally "breaking" (at runtime)

Testing Plan

• Unit Tests: all existing tests
• Persistence Tests: n/a
• Integration Tests: n/a
• Compatibility Tests: n/a

Rollout Plan

• autobots, which are self-rolling-out.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.61%. Comparing base (1fd8ba0) to head (3e71788).

Files with missing lines	Coverage Δ
internal/internal_task_handlers.go	81.79% <100.00%> (+0.17%)	⬆️

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