[bazel] improve bitstream/verilator build cacheability #4505

Job	Run time
Lint (quick)	3m 10s
Lint (slow)	11m 52s
Build documentation	5m 33s
Airgapped build	9m 41s
Run OTBN crypto tests	2m 44s
Run OTBN smoke Test	2m 33s
Verilated Earl Grey	1h 12m 13s
Verible lint	1m 12s
Verilated English Breakfast	7m 25s
Build Docker Containers	2m 58s
Build and test software	13m 38s
CW305's Bitstream	22m 28s
Earl Grey for CW310 / Build bitstream	1h 2m 55s
Earl Grey for CW340 / Build bitstream	1h 26m 39s
Earl Grey for CW310 Hyperdebug / Build bitstream	1h 9m 26s
CW310 Test ROM Tests / FPGA test	3m 29s
CW310 ROM Tests / FPGA test	41m 18s
CW340 ROM_EXT Tests / FPGA test	6m 13s
CW340 SiVal Tests / FPGA test	17m 12s
CW340 ROM Tests / FPGA test	40s
CW340 Manufacturing Tests / FPGA test	40m 53s
CW340 Test ROM Tests / FPGA test	3m 6s
CW340 SiVal ROM_EXT Tests / FPGA test	3m 57s
Cache bitstreams to GCP	0s
CW310 Manufacturing Tests / FPGA test	34m 17s
CW310 SiVal Tests / FPGA test	26m 26s
CW310 SiVal ROM_EXT Tests / FPGA test	43m 25s
CW310 ROM_EXT Tests / FPGA test	11m 32s
Verify FPGA jobs	23s
	10h 7m 18s

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