Small speed up to update_headers

[bdraco]

What do these changes do?

• Avoid checking to see if the port is default if no port is set: For most cases we can avoid the is_default_port check which has to work out the default port internally in yarl since if there is no explict port set, it must be the default port
• Avoid using strip for a single char check

Event if we have to call is_default_port, explict_port will already be cached

Are there changes in behavior for the user?

no

Is it a substantial burden for the maintainers to support this?

no

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.56%. Comparing base (e3b1011) to head (a471866).
Report is 7 commits behind head on master.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9366   +/-   ##
=======================================
  Coverage   98.56%   98.56%           
=======================================
  Files         107      107           
  Lines       34981    34984    +3     
  Branches     4149     4150    +1     
=======================================
+ Hits        34478    34481    +3     
  Misses        335      335           
  Partials      168      168           

Flag	Coverage Δ
CI-GHA	98.44% <100.00%> (+<0.01%)	⬆️
OS-Linux	98.10% <100.00%> (+<0.01%)	⬆️
OS-Windows	96.52% <100.00%> (+<0.01%)	⬆️
OS-macOS	97.79% <100.00%> (+<0.01%)	⬆️
Py-3.10.11	97.67% <100.00%> (+<0.01%)	⬆️
Py-3.10.15	97.60% <100.00%> (+<0.01%)	⬆️
Py-3.11.10	97.67% <100.00%> (-0.01%)	⬇️
Py-3.11.9	97.73% <100.00%> (-0.02%)	⬇️
Py-3.12.6	98.15% <100.00%> (+<0.01%)	⬆️
Py-3.13.0-rc.2	98.14% <100.00%> (+<0.01%)	⬆️
Py-3.9.13	97.56% <100.00%> (+<0.01%)	⬆️
Py-3.9.20	97.50% <100.00%> (+<0.01%)	⬆️
Py-pypy7.3.16	97.12% <100.00%> (+<0.01%)	⬆️
VM-macos	97.79% <100.00%> (+<0.01%)	⬆️
VM-ubuntu	98.10% <100.00%> (+<0.01%)	⬆️
VM-windows	96.52% <100.00%> (+<0.01%)	⬆️

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[patchback]

Backport to 3.10: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply 43deadb on top of patchback/backports/3.10/43deadb286df2a05de09d00121ed90811ca232a2/pr-9366

Backporting merged PR #9366 into master

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https://github.com/aio-libs/aiohttp.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.10/43deadb286df2a05de09d00121ed90811ca232a2/pr-9366 upstream/3.10

4. Now, cherry-pick PR Small speed up to update_headers #9366 contents into that branch:

   $ git cherry-pick -x 43deadb286df2a05de09d00121ed90811ca232a2

   If it'll yell at you with something like fatal: Commit 43deadb286df2a05de09d00121ed90811ca232a2 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x 43deadb286df2a05de09d00121ed90811ca232a2

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Small speed up to update_headers #9366 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.10/43deadb286df2a05de09d00121ed90811ca232a2/pr-9366

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[patchback]

Backport to 3.11: 💚 backport PR created

✅ Backport PR branch: patchback/backports/3.11/43deadb286df2a05de09d00121ed90811ca232a2/pr-9366

Backported as #9382

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.