Remove our macOS-only task-info crate (#41132)

This crate is just using system APIs to get the resident and virtual
memory size of the current process. We can do this directly with
`mach2`, which also allows more flexibility if we want to fetch other
values in the future.

This does require duplicating `mach2` as the version used by `gilrs` is
older. Presumably, some future release of `gilrs` will upgrade soon.

Testing: There aren't really tests for this, but I tested it manually by
running the memory reporter and ensuring that both the old and new
values were
the same.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

deny.toml

@@ -122,8 +122,9 @@ skip = [
     # rust-content-security-policy uses newest base64.
     "base64",
 
-    # gilrs is on 0.10.0, but Servo is still on 0.9.4
+    # Duplicated by gilrs.
     "core-foundation",
+    "mach2",
 
     # wgpu crates still depend on 1.1.0
     "rustc-hash",