Change: move total counting out of print_report_xml_start

[mattmundell]

What

Move the counting of the result totals out of print_report_xml_start.

This PR starts by moving some key variables in print_report_xml_start into the ctx struct. Then it moves the block that does result counting out to a new function print_report_get_totals. Moving the variables allows print_report_get_totals to take a single arg. The function also uses that single arg to pass the counts back to the caller.

Note that, as with previous PRs, the variables moved into the struct print_report_context are automatically initialized to zero, due to the init of the struct: print_report_context_t ctx = {0};.

Why

Another small step in reducing the size of print_report_xml_start, so that it's easier to understand and maintain.

References

Follows /pull/2669

Testing

I got a single report with the PR, then got the same report on the main branch. I made sure they were the same. I did that with two timezones just to be sure (using the timezone term in the filter).

o m m '<get_reports report_id="92a09ffd-a5bd-464b-9f2c-54b78ec5ebcf" details="1" filter="timezone=Pacific/Auckland rows=3 apply_overrides=1 min_qod=60"/>' > /tmp/r-auk-main
o m m '<get_reports report_id="92a09ffd-a5bd-464b-9f2c-54b78ec5ebcf" details="1" filter="timezone=Europe/Berlin rows=3 apply_overrides=1 min_qod=60"/>' > /tmp/r-ber-main
diff /tmp/r-auk /tmp/r-auk-main
diff /tmp/r-ber /tmp/r-ber-main

[mattmundell]

@a-h-abdelsalam Thank you!