ci: clean up sdk-platform-java test names #1435

Job	Run time
filter	1m 1s
build(8) for showcase	9m 43s
sdk-platform-java units (8)	4m 23s
gapic-generator-java (8)	11m 3s
sdk-platform-java self-service clients (11)	9m 4s
sdk-platform-java self-service clients (17)	9m 11s
java8-compatibility	5m 15s
showcase-clirr	4m 51s
gapic-generator-java-bom	2m 31s
unmanaged_dependency_check	12m 1s
sdk-platform-java units (21)	3m 59s
sdk-platform-java integration (21)	9m 7s
sdk-platform-java integration (11)	10m 8s
sdk-platform-java units (17)	4m 12s
sdk-platform-java integration (17)	9m 51s
sdk-platform-java units (11)	4m 23s
sdk-platform-java integration (25)	9m 59s
showcase (11)	13m 39s
showcase (25)	13m 0s
dependency_analyzer_unit_test	1m 22s
showcase (17)	13m 1s
showcase (21)	14m 0s
sdk-platform-java units (25)	3m 15s
	2h 58m 59s

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