Fix flakey formatDate tests#67845
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pkozlowski-opensource merged 2 commits intoangular:mainfrom Mar 26, 2026
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Removes the 'America/New_York' timezone string test case from `formatDate` tests because the underlying `Date.parse` API does not support IANA timezone strings. This caused the timezone calculation to silently fall back to the local executing machine's timezone, leading to non-deterministic test flakiness on Remote Build Execution (RBE) workers operating in varying geographic locations.
Replaced testing constructions of `Date` objects from `formatDate` tests from plain ISO strings over to 'new Date(year, month, date)'.
Instantiating 'new Date("2024-01-01")' parses the string strictly as UTC midnight ("2024-01-01T00:00:00.000Z"). When local operations execute (such as calculating `getThursdayThisIsoWeek` boundaries), the UTC date shifts relative to the executing machine's timezone. For example, in PST (GMT-8), that date translates exactly to 'December 31st 16:00:00', pushing week boundaries backwards.
By wrapping date constructs explicitly as 'new Date(2024, 0, 1)', it natively guarantees local midnight execution and prevents boundaries shifting on global CI Remote Build Execution (RBE) workers.
Example (from a machine in PST):
```javascript
> new Date('2024-01-01')
Sun Dec 31 2023 16:00:00 GMT-0800 (Pacific Standard Time)
> new Date(2024, 0, 1)
Mon Jan 01 2024 00:00:00 GMT-0800 (Pacific Standard Time)
```
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JeanMeche
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Mostly generated by Gemini, fixing some flakey tests which were accidentally using device local time, which can vary for Bazel tests based on the location of RBE instances.