Add from-loop tests

[titsuki]

Fix #114

I have added tests for the from-loop method according to the following page
https://doc.perl6.org/routine/from-loop#class_Seq

But I don't have very much confidence. Can anyone review this tests ?

The following is the results of the from-loop tests

not ok 29 - from-loop(&body) returns a Seq

# Failed test 'from-loop(&body) returns a Seq'
# at ./S32-list/seq.t line 133
ok 30 - the Seq object is lazy
not ok 31 - from-loop(&body, &condition) returns a Seq

# Failed test 'from-loop(&body, &condition) returns a Seq'
# at ./S32-list/seq.t line 137
ok 32 - from-loop(&body, &condition) terminates calling &body if &condition returns False
not ok 33 - from-loop(&body, &condition, &afterward) returns a Seq

# Failed test 'from-loop(&body, &condition, &afterward) returns a Seq'
# at ./S32-list/seq.t line 143
ok 34 - &afterward is called after each call to &body.
ok 35 - from-loop(&body, &condition, &afterward) terminates calling &body if &condition returns False

[titsuki]

Sorry, I have fixed the way to check the returned type.
And the following is the results

ok 29 - from-loop(&body) returns a Seq
ok 30 - the Seq object is lazy
ok 31 - from-loop(&body, &condition) returns a Seq
ok 32 - from-loop(&body, &condition) terminates calling &body if &condition returns False
ok 33 - from-loop(&body, &condition, &afterward) returns a Seq
ok 34 - &afterward is called after each call to &body.
ok 35 - from-loop(&body, &condition, &afterward) terminates calling &body if &condition returns False

[salortiz]

@titsuki
The type of an object can be tested by

isa-ok Seq.from-loop({ 1 }), Seq, "Bla, bla";

and you can avoid the coercion to Array using a Scalar variable (or sigilless):

     my $foo = Seq.from-loop({ 1 });
     ok $foo.is-lazy, …

[titsuki]

@salortiz
Thank you for your advice !
I have fixed your pointer.