tests: move proto roundtrip json to .tmp/

[paulirish]

#6183 added this file and at the time it was tracked in source control

in #10557 we added the file to gitignore

now that it's ignored, seems like it can be in dist rather than nestled amongst tracked files.

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i went with dist because #10994 but i suppose if we're not sharing artifacts between builds.... perhaps this makes more semantic sense in .tmp ?

[connorjclark]

yeah this was an annoyance when I was relying on dependencies and artifacts during experimentation. great change.

although the above is not relevant any more so I agree doing .tmp makes more semantic sense. even if some other job needs that file ... i'd rather upload tmp as a separate artifact than use dist.

[patrickhulce]

I'll defer my review if @connorjclark has feelings here. I have no strong preference 🤷

[brendankenny]

another vote for .tmp (or wherever that's not dist/).

It shouldn't be a hard and fast rule, but it's nice to keep dist/ to things that are intended to actually be distributed (in one way or the other).

[paulirish]

.tmp done