d_bg_w_kcol work

[caseif]

A little bit of work on d_bg_w_kcol. The actual changeset is pretty small relative to the whole class, but this file is incredibly tedious to work on.

[decomp-dev]

Report for GZ2E01 (0a899a4 - 294a20d)

📈 2 improvements in unmatched functions:

Unit	Function	Bytes	Before	After
framework/d/d_bg_w_kcol	dBgWKCol::WallCorrectSort(dBgS_Acch*)	+3643	0.11%	98.67%
framework/d/d_bg_w_kcol	dBgWKCol::LineCheck(cBgS_LinChk*)	+30	98.04%	99.51%

📉 1 regressions in unmatched functions:

Unit	Function	Bytes	Before	After
framework/d/d_bg_w_kcol	dBgWKCol::CaptPoly(dBgS_CaptPoly&)	-13	97.80%	96.65%

[caseif]

The regression in CaptPoly isn't due to any specific change and seems to mostly be related to register shuffling - the debug version actually has a significant improvement (~86% -> ~93%).