Add test for filtering out multiple initial values in filter gen

tests/SelfTest/Baselines/compact.sw.approved.txt

tests/SelfTest/Baselines/console.std.approved.txt

tests/SelfTest/Baselines/console.sw.approved.txt

tests/SelfTest/Baselines/junit.sw.approved.txt

tests/SelfTest/Baselines/sonarqube.sw.approved.txt

tests/SelfTest/Baselines/tap.sw.approved.txt

tests/SelfTest/Baselines/xml.sw.approved.txt

tests/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp