ci: clean up sdk-platform-java test names #17961

Job	Run time
generate-readme	1m 6s
gapic-bom	1m 34s
root-pom	1m 42s
package_name_check	1m 0s
owlbot-py	1m 7s
gitignore_correctness	1m 2s
owlbot-yaml	1m 1s
group_id_check_for_maps_libraries	8m 11s
	16m 43s

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