src: cut small costs in node::MakeCallback

[nigrosimone]

After #66316, node::MakeCallback still does some work that the common case does not need:

• it enters the Environment's context also when it is already the entered and current one
• it sets the async context frame also when it does not change (usually undefined before and after): now async_context_frame::exchange() skips the set, for every caller
• push_async_context() takes the resource variant by value
• the native resource stack uses resize() where push_back() and pop_back() are enough

Each one is 1-5 ns, together about 14-16 ns per call. type=Call does not use this code. benchmark/compare.js, 30 runs, Linux x64:

                                                    confidence improvement accuracy (*)   (**)  (***)
napi/make_callback n=1000000 type='AsyncResource'           ***      9.10 %  ±4.88% ±6.51% ±8.49%
napi/make_callback n=1000000 type='Call'                            -0.76 %  ±5.76% ±7.66% ±9.97%
napi/make_callback n=1000000 type='MakeCallback'            ***     13.24 %  ±6.31% ±8.40% ±10.93%
napi/make_callback n=10000000 type='AsyncResource'           **      8.68 %  ±5.17% ±6.89% ±8.98%
napi/make_callback n=10000000 type='Call'                           -1.65 %  ±6.17% ±8.21% ±10.69%
napi/make_callback n=10000000 type='MakeCallback'           ***     11.56 %  ±2.91% ±3.87% ±5.04%

Refs: nodejs/performance#24

Disclosure: I used Opus 5.5 (Max) as coding assistant

[codecov]

Codecov Report

❌ Patch coverage is 82.35294% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.38%. Comparing base (1f26576) to head (8acef08).
⚠️ Report is 34 commits behind head on main.

Files with missing lines	Patch %	Lines
src/api/callback.cc	57.14%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66395      +/-   ##
==========================================
+ Coverage   90.35%   90.38%   +0.03%     
==========================================
  Files         792      792              
  Lines      275500   275592      +92     
  Branches    52791    52848      +57     
==========================================
+ Hits       248932   249105     +173     
+ Misses      16992    16893      -99     
- Partials     9576     9594      +18     

Files with missing lines	Coverage Δ
src/async_context_frame.cc	100.00% <100.00%> (ø)
src/env.cc	82.22% <100.00%> (-0.01%)	⬇️
src/env.h	97.40% <ø> (+0.06%)	⬆️
src/api/callback.cc	81.94% <57.14%> (-1.47%)	⬇️

... and 39 files with indirect coverage changes

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[github-actions]

Benchmark GHA (napi / make_callback): https://github.com/nodejs/node/actions/runs/36693603945

Results

[!WARNING]
Do not take GHA benchmark results as face value, always confirm them
using a dedicated machine, e.g. Jenkins CI.

Benchmark results:

[!WARNING]
Do not take GHA benchmark results as face value, always confirm them
using a dedicated machine, e.g. Jenkins CI.

[nigrosimone]

Benchmark GHA (napi / make_callback): https://github.com/nodejs/node/actions/runs/36693603945

@addaleax The GHA benchmark could not load the binding ("Binding failed to load" in every job): the workflow runs make build-ci but never make bench-addons-build, so no napi/* benchmark can run there. The table in the description is benchmark/compare.js on my machine.