net/http: skip TestClientTimeout_h{1,2} on windows/arm and windows/arm64
net/http: skip TestClientTimeout_h{1,2} on windows/arm and windows/arm64

These tests are empirically flaky on the windows/arm and windows/arm64
builders, with a consistent (but rare) failure mode.

This change skips the test if that particular failure mode is
encountered on those platforms; the skip can be removed if and when
someone has the time to pin down the root cause.

For #43120

Change-Id: Ie3a9a06bf47e3a907c7b07441acc1494a4631135
Reviewed-on: https://go-review.googlesource.com/c/go/+/375635
Trust: Bryan Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
Run-TryBot: Bryan Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
Reviewed-by: Damien Neil <7e091e9a80da888fcd7836fd3c6b7b85f4677c12@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

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