The tracing code assumes that query_option_names and query_option_values
vectors always have the same length as the prepared_statements vector,
but it's not true. E.g. if one of the statements in a batch is
incorrect, it will create a discrepancy between the number of prepared
statements and the number of bound names and values, which currently
leads to a segmentation fault.
To overcome the problem, all three vectors are integrated into a single
vector, which makes size mismatches impossible.
Tested manually with code that triggers a failure while executing
a batch statement, because the Python driver performs driver-side
validation and thus it's hard to create a test case which triggers
the problem.
closes: #9221
ec52e05eab