remove hard coded "/tmp" in ansible-test injector paths

[simonLeary42]

fixes #82214

Not entirely clear on why this was hardcoded in the first place, so there might be some good reason not to do this.

[simonLeary42]

@mattclay git balme says you wrote these lines, do you know why it was hardcoded this way?

[webknjaz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mattclay]

@mattclay git balme says you wrote these lines, do you know why it was hardcoded this way?

There are two issues that can occur when using the default temporary directory:

1. The directory may not be accessible by other users. When that occurs, it breaks integration tests which switch users.
2. The directory may have a long enough path that it causes script shebangs to exceed the 127 character limit on Linux.

[simonLeary42]

since all CI checks pass, I assume that both of the above problems are caused by linux users setting their temp dir to something non-standard. If it's between mac users as a whole and a small subset of linux users, I would assume that it makes more sense to choose mac users. If these linux users were clever enough to set the TMP environment variable equal to a very deeply nested subdirectory without o+w and the sticky bit set, then they are clever enough to let ansible-test run with TMP unset.