Fixed argument_parser_test to account for argv requiring that the first element be the executable name
Fixed argument_parser_test to account for argv requiring that the first element be the executable name

stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/stan,stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/stan