Update TPUSpawnPlugin spawn methods

[awaelchli]

What does this PR do?

Part of #9987
Follow up to #10018

Adds the spawn method also to the tpu plugin and refactors existing usages of xmp.spawn to use the new method.

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Did you have fun?

I made sure I had fun coding 🙃

[tchaton]

LGTM !

[codecov]

Codecov Report

Merging #10022 (f9a4db9) into master (854bdc0) will decrease coverage by 4%.
The diff coverage is 46%.

@@           Coverage Diff            @@
##           master   #10022    +/-   ##
========================================
- Coverage      93%      89%    -4%     
========================================
  Files         179      180     +1     
  Lines       15842    15872    +30     
========================================
- Hits        14658    14077   -581     
- Misses       1184     1795   +611