Port #20198 to v3
Port #20198 to v3

ScrollSpy unit test: Use single done() in a then() instead of multiple done()s

Fixes test flakiness on OS X Safari and Android when using jQuery 3.
Fixes #20182 more
Refs #20191

RanHoNg/bootstrap,scjang/ssss,OneZenD/gr8alpha,LuoSpark/bootstrap,OneZenD/gr8alpha,bo01ean/bootstrap,devsong/bootstrap,algolia/bootstrap,michael-brade/bootstrap,KM-MFG/bootstrap,scjang/ssss,michael-brade/bootstrap,antonaavik/bootstrap,LimetecBiotechnologies/bootstrap,bo01ean/bootstrap,FernandezR/bootstrap,hiersekornc/bootstrap,seoulstore/ssss,df2k2/bootstrap,OneZenD/gr8alpha,aoimedia/bootstrap,OneZenD/gr8alpha,stone2310/bootstrap,algolia/bootstrap,hbrls/bootstrap,LimetecBiotechnologies/bootstrap,nanuclickity/bootstrap,mdo/bootstrap,stone2310/bootstrap,antonaavik/bootstrap,KM-MFG/bootstrap,LuoSpark/bootstrap,algolia/bootstrap,LuoSpark/bootstrap,mosoft521/bootstrap,LimetecBiotechnologies/bootstrap,scjang/ssss,hbrls/bootstrap,michael-brade/bootstrap,Softdocs/bootstrap,Softdocs/bootstrap,hbrls/bootstrap,patrickhlauke/bootstrap,antonaavik/bootstrap,monoblaine/bootstrap,panvagil/bootstrap,patrickhlauke/bootstrap,mdo/bootstrap,mosoft521/bootstrap,justincron/bootstrap,JobsUnited/bootstrap,Softdocs/bootstrap,monoblaine/bootstrap,stone2310/bootstrap,GerHobbelt/bootstrap,bkrukowski/bootstrap,seoulstore/ssss,the-open-university/ouice-bootstrap,nanuclickity/bootstrap,KM-MFG/bootstrap,RanHoNg/bootstrap,mosoft521/bootstrap,hiersekornc/bootstrap,FernandezR/bootstrap,292388900/bootstrap-1,df2k2/bootstrap,seoulstore/ssss,FernandezR/bootstrap,Jazzo/bootstrap,devsong/bootstrap,panvagil/bootstrap,seoulstore/ssss,RanHoNg/bootstrap,bo01ean/bootstrap,scjang/ssss,gencer/bootstrap,justincron/bootstrap,mdo/bootstrap,the-open-university/ouice-bootstrap,FernandezR/bootstrap,patrickhlauke/bootstrap,JobsUnited/bootstrap,gencer/bootstrap,justincron/bootstrap,devsong/bootstrap,monoblaine/bootstrap,bkrukowski/bootstrap,aoimedia/bootstrap,hiersekornc/bootstrap,nanuclickity/bootstrap,justincron/bootstrap,GerHobbelt/bootstrap,JobsUnited/bootstrap,gencer/bootstrap,the-open-university/ouice-bootstrap,hiersekornc/bootstrap,GerHobbelt/bootstrap,df2k2/bootstrap,292388900/bootstrap-1,df2k2/bootstrap,hbrls/bootstrap,aoimedia/bootstrap,Jazzo/bootstrap,Jazzo/bootstrap,antonaavik/bootstrap,panvagil/bootstrap