perf(bytecompiler): avoid redundant Constant clone in IC initialization

[tkshsbcue]

perf(bytecompiler): avoid redundant Constant clone in IC initialization

Description

emit_get_property_by_name and emit_set_property_by_name were cloning the entire Constant enum to extract the inner JsString, which was then cloned again for the InlineCache. This meant two JsString clones per property access site during compilation when only one is needed.

The fix borrows the constant by reference and clones only the JsString once.

Before

let Constant::String(ref name) = self.constants[name_index as usize].clone() else {
    unreachable!("there should be a string at index")
};
self.ic.push(InlineCache::new(name.clone()));

1. .clone() on the Constant enum clones the inner JsString
2. name.clone() clones the JsString again for the InlineCache

After

let Constant::String(name) = &self.constants[name_index as usize] else {
    unreachable!("there should be a string at index")
};
let name = name.clone();
self.ic.push(InlineCache::new(name));

1. Borrow by reference — no clone
2. Single JsString clone, moved directly into the InlineCache

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	53,125	53,125	0
Passed	50,827	50,827	0
Ignored	1,482	1,482	0
Failed	816	816	0
Panics	0	0	0
Conformance	95.67%	95.67%	0.00%

Tested main commit: f6021b3d3dd1249c9569be77f0ca9ccf00ea318a
Tested PR commit: 832efafc0ff6da7e9ee6433d264c03a8613db114
Compare commits: f6021b3...832efaf

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.70%. Comparing base (6ddc2b4) to head (832efaf).
⚠️ Report is 929 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5299       +/-   ##
===========================================
+ Coverage   47.24%   59.70%   +12.45%     
===========================================
  Files         476      589      +113     
  Lines       46892    63490    +16598     
===========================================
+ Hits        22154    37906    +15752     
- Misses      24738    25584      +846     

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[zhuzhu81998]

hmm do you really need to introduce this? doesnt look necessary if you dont override name below.