feat: add support for nested transaction rollbacks via savepoints in sql #11915

Job	Run time
Test vitess_5_7 (graphql) on Linux	1m 28s
Test vitess_5_7 (json) on Linux	1m 33s
Test vitess_8_0 (graphql) on Linux	1m 29s
Test vitess_8_0 (json) on Linux	1m 55s
Test postgres15 (graphql) on Linux	17m 24s
Test postgres15 (json) on Linux	15m 34s
Test mssql_2022 (graphql) on Linux	7m 17s
Test mssql_2022 (json) on Linux	9m 15s
Test mongodb_4_2 (graphql) on Linux	3m 10s
Test mongodb_4_2 (json) on Linux	3m 42s
Test cockroach_23_1 (graphql) on Linux	27m 34s
Test cockroach_23_1 (json) on Linux	30m 51s
Test cockroach_22_2 (graphql) on Linux	22m 53s
Test cockroach_22_2 (json) on Linux	23m 59s
Test cockroach_22_1_0 (graphql) on Linux	24m 32s
Test cockroach_22_1_0 (json) on Linux	24m 39s
	3h 37m 15s

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