Add patch file for BITALG and VL for VPOPCNTDQ

[vsivsi]

See discussion here: https://github.com/mmcloughlin/avo/pull/199#issuecomment-969320610

[codecov-commenter]

Codecov Report

Merging #234 (1702e56) into master (ead3fb5) will increase coverage by 0.00%. The diff coverage is 80.00%.

@@           Coverage Diff           @@
##           master     #234   +/-   ##
=======================================
  Coverage   75.92%   75.92%           
=======================================
  Files          65       65           
  Lines       20694    20719   +25     
=======================================
+ Hits        15711    15731   +20     
- Misses       4901     4906    +5     
  Partials       82       82           

Flag	Coverage Δ
integration	11.91% <0.00%> (-0.02%)	:arrow_down:
stress	?
unittests	73.01% <80.00%> (+<0.01%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
x86/zoptab.go	92.42% <ø> (ø)
build/zinstructions.go	67.65% <66.66%> (-0.01%)	:arrow_down:
x86/zctors.go	100.00% <100.00%> (ø)

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[vsivsi]

@mmcloughlin This PR is also now fully merged with upstream and ready to go. I took inspiration from the GFNI PR #344 and backed-out the editing of x86_64.xml I agree, that was a real pain and unsustainable. Using the "opcodesextra" mechanism worked out great.

There was only one wrinkle with this approach, but in the end it seems fine: because x86_64.xml already defines VPOPCNTD and VPOPCNTQ, but without the 128/256 bit "VL" operand forms, the only way to get this to work was to completely redefine and override those two instructions here. There didn't seem to be a clean existing way to "upgrade" the forms already present in x86_64.xml with the VL forms.

[mmcloughlin]

Landed in #361 #362.

Thanks!