Restore filtering of non-src files

[fredrikekre]

This patch restores the filtering of non-src files that was lost
in #767. After JuliaLang/julia#49866,
Base.parse_cache_header returns both the non-filtered and filtered
list instead of doing filtering internally based on the
srcfiles_only::Bool keyword argument.

There is a test for this failure mode that fails on Revise master branch
and passes with this patch (see

Revise.jl/test/runtests.jl

Lines 3070 to 3080 in 1059181

	do_test("Non-jl include_dependency (issue #388)") && @testset "Non-jl include_dependency (issue #388)" begin
	push!(LOAD_PATH, joinpath(@__DIR__, "pkgs"))
	@eval using ExcludeFile
	sleep(0.01)
	pkgdata = Revise.pkgdatas[Base.PkgId(UUID("b915cca1-7962-4ffb-a1c7-2bbdb2d9c14c"), "ExcludeFile")]
	files = Revise.srcfiles(pkgdata)
	@test length(files) == 2
	@test joinpath("src", "ExcludeFile.jl") ∈ files
	@test joinpath("src", "f.jl") ∈ files
	@test joinpath("deps", "dependency.txt") ∉ files
	end

).