[Performance] Memoize platformAndArch and use startsWith

[gonzaloriestra]

Optimizes platformAndArch by adding memoization for the default case and using a more efficient string check for Windows detection. This reduces overhead in frequent operations like analytics reporting.

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PR created automatically by Jules for task 15461649029740018611 started by @gonzaloriestra

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[isaacroldan]

We are adding complexity for no real benefit here. We save a string match but add memoization and other string checks. The complexity is not worth it, we are literally saving 0ms: platformAndArch is called onlye once or maybe maybe twice in a normal run.

[gonzaloriestra]

I wanted to check how many times this was used before sharing it, but I forgot about it... You are right that it's only 1 or 2, so it's not worth it. Thanks!