dev/core#3922 Fix fiscal year end when fiscal year starts on Jan 1.

[larssandergreen]

Before

With previous_n.fiscal_year, the dates were correct if a fiscal year start date other than Jan 1 was set. If Jan 1 was the FY start date, then the year was one too large.

After

Correct fiscal year end date for Jan 1 and other FY start dates.

Thanks @demeritcowboy for noticing this one.

[civibot]

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[demeritcowboy]

Unit test is at #24769

I might suggest adding a code comment in here because someone will come along and say "hey we can simplify this because $from['Y'] + $relativeTermSuffix is the same as $fYear"

[larssandergreen]

Done, thanks Dave.