asserts: False positives on Set/non-Set equality

[thunderk]

Describe the bug

Equality assertion in testing is wrongly true, when comparing a Set with another type of object.

To Reproduce

In REPL:

> const {equal} = await import("./testing/asserts.ts");
> equal(new Set([1]), {});
true

System

Tested on [email protected], [email protected] and [email protected].

deno 1.12.0 (release, x86_64-unknown-linux-gnu)
v8 9.2.230.14
typescript 4.3.2

[bartlomieju]

Should be fixed by #1000

[gtramontina]

FYI, #1000 is now merged.

[thunderk]

I confirm that it fixes this issue too, thanks!