Convert tests to use v3

[forsyth2]

Request criteria

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Issue description

The tests currently use v2. Now that v3 simulation data is (or will soon be) available, we should convert the tests to use that instead. This will involve mapping file and grid changes, as in #548 (comment).

[forsyth2]

When this is implemented, we should reduce the test data size. The v2 data took up 24 terabytes, which is not an acceptable long-term solution. (See discussion on #561).