perf: Memory optimizations #822

Job	Run time
units (8)	39s
units (17)	36s
units (21)	38s
dependencies (17)	36s
windows	59s
lint	54s
javadoc	34s
units (11)	42s
integration / integration-spanner (11)	6m 45s
clirr	28s
integration / integration-cassandra (11)	3m 8s
	15m 59s

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