Replace all instances of ; in the rowparser loop with , ( ~15% speedup )

Replace all instances of ; in the rowparser loop with , ( ~15% speedup )

The functional diff best examined via `... --color-words -w lib ...`

This is another microoptimization, which is nevertheless measurable on 1000+
row resultsets. Investigation into this was prompted by a curious comment made
by bulk88[1] in response to xdg[2]:

  Every ";" is an op that executes that adjusts current line number

Given that we already generate all this code, and it is not intended to be
read by a human, swapping ; with , is only logical. A (very very crude) check
with the included benchmarker indeed shows a repeatable difference on 5.16.2

[1] http://www.nntp.perl.org/group/perl.perl5.porters/2015/05/msg228074.html
[2] http://www.nntp.perl.org/group/perl.perl5.porters/2015/05/msg228068.html