iszero/isone aren't efficient on InfRanges

[DanielVandH]

julia> using InfiniteArrays

julia> findfirst(isone, 1:∞) # works because it checks each element one at a time
1

julia> findfirst(isone, 2:∞) # never finds it, so hangs
WARNING: Force throwing a SIGINT
ERROR: InterruptException:
Stacktrace:
 [1] getindex
   @ C:\Users\User\.julia\packages\InfiniteArrays\7v9AI\src\infrange.jl:0 [inlined]
 [2] findnext(testf::typeof(isone), A::InfiniteArrays.InfUnitRange{Int64}, start::Int64)
   @ Base .\array.jl:2155
 [3] findfirst(testf::Function, A::InfiniteArrays.InfUnitRange{Int64})
   @ Base .\array.jl:2206
 [4] top-level scope
   @ REPL[9]:1

julia> ^C

julia> findfirst(iszero, 0:∞)
1

julia> findfirst(iszero, 1:∞)
WARNING: Force throwing a SIGINT
ERROR: InterruptException:
Stacktrace:
 [1] getindex
   @ C:\Users\User\.julia\packages\InfiniteArrays\7v9AI\src\infrange.jl:0 [inlined]
 [2] findnext(testf::typeof(iszero), A::InfiniteArrays.InfUnitRange{Int64}, start::Int64)
   @ Base .\array.jl:2155
 [3] findfirst(testf::Function, A::InfiniteArrays.InfUnitRange{Int64})
   @ Base .\array.jl:2206
 [4] top-level scope
   @ REPL[11]:1

julia> findfirst(==(0), 1:∞) # efficient

julia> findfirst(==(1), 2:∞)

These calls are a bit specific so not much of a priority, but the methods in

InfiniteArrays.jl/src/infrange.jl

Lines 580 to 601 in 0049f1b

	for op in (:isequal, :(==))
	@eval begin
	findfirst(p::Fix2{typeof($op),T}, r::InfStepRange{T,S}) where {T,S} =
	_step_findfirst(p, r)
	findfirst(p::Fix2{typeof($op),T}, r::InfStepRange{T,<:Integer}) where {T<:Integer} =
	_step_findfirst(p, r)
	findfirst(p::Fix2{typeof($op),<:Integer}, r::InfStepRange{<:Integer,<:Integer}) =
	_step_findfirst(p, r)
	function findfirst(p::Fix2{typeof($op),<:Integer}, r::AbstractInfUnitRange{<:Integer})
	first(r) <= p.x || return nothing
	p.x - first(r) + 1
	end
	findfirst(p::Fix2{typeof($op),<:Number}, r::AbstractInfUnitRange{<:Integer}) =
	isinteger(p.x) ? findfirst($op(convert(Integer, p.x)), r) : nothing
	findfirst(p::Fix2{typeof($op),<:Number}, r::InfStepRange{<:Integer,<:Integer}) =
	isinteger(p.x) ? findfirst($op(convert(V, p.x)), r) : nothing
	end
	end

could perhaps be used so that findfirst(iszero, <:InfRanges) uses findfirst(==(0), <:InfRanges) and similarly for isone.