chore: move bigquery jdbc external test to monorepo #17232

Job	Run time
owlbot-py	1m 19s
owlbot-yaml	1m 1s
gapic-bom	1m 50s
gitignore_correctness	1m 9s
package_name_check	1m 4s
group_id_check_for_maps_libraries	7m 58s
root-pom	1m 41s
generate-readme	1m 14s
	17m 16s

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