fix(builtins/function/mod,function/arguments,function/bound,object/mod): convert panics to EngineError::Panic using js_expect

[KaustubhOG]

Part of #3241.

It changes the following:

• core/engine/src/builtins/function/arguments.rs: converted 7 panics (7× js_expect on downcast_ref::<MappedArguments>() exotic method calls); binding_indices retains .expect("binding must exist") as a documented
  compiler invariant — binding existence is guaranteed by bound_names(formals)
• core/engine/src/builtins/function/mod.rs: converted 10 panics (2× downcast_ref::<OrdinaryFunction>(), 3× vm.frames.last() frame existence, 1× to_integer_or_infinity, 1× define_property_or_throw length, 1× define_property_or_throw name, 1× new.target object cast, 1× set_function_name) to use js_expect
• core/engine/src/builtins/function/bound.rs: converted 2 panics (2× downcast_ref::<BoundFunction>() exotic method calls) to use js_expect
• core/engine/src/builtins/object/mod.rs: converted 10 panics (6× CreateDataPropertyOrThrow
• from_property_descriptor, 1× create_data_property_or_throw in group_by,1× create_data_property_or_throw in get_own_property_descriptors,1× toObject in to_string, 1× ToObject in assign) to use js_expect

[KaustubhOG]

Note: set_function_name was changed from -> () to -> JsResult<()>. Call sites in vm/opcode/define/class/ and vm/opcode/set/property.rs were updated only to propagate this cascade ,remaining .expect() calls in those files are left because vm opcodes are a separate batch (after /builtins complete) in #3241

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	52,963	52,963	0
Passed	49,901	49,901	0
Ignored	2,222	2,222	0
Failed	840	840	0
Panics	0	0	0
Conformance	94.22%	94.22%	0.00%

Tested main commit: a49348586d90b790936dc6ab651da6aff3f60e67
Tested PR commit: bef34cd145106537cbd9da7625ff84670b8f72ab
Compare commits: a493485...bef34cd

[codecov]

Codecov Report

❌ Patch coverage is 61.11111% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.29%. Comparing base (6ddc2b4) to head (bef34cd).
⚠️ Report is 819 commits behind head on main.

Files with missing lines	Patch %	Lines
core/engine/src/vm/opcode/define/class/setter.rs	25.00%	3 Missing ⚠️
core/engine/src/builtins/function/arguments.rs	33.33%	2 Missing ⚠️
core/engine/src/builtins/function/bound.rs	0.00%	2 Missing ⚠️
core/engine/src/builtins/function/mod.rs	71.42%	2 Missing ⚠️
core/engine/src/vm/opcode/define/class/getter.rs	50.00%	2 Missing ⚠️
core/engine/src/vm/opcode/define/class/method.rs	50.00%	2 Missing ⚠️
core/engine/src/builtins/proxy/mod.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5001       +/-   ##
===========================================
+ Coverage   47.24%   58.29%   +11.05%     
===========================================
  Files         476      559       +83     
  Lines       46892    61408    +14516     
===========================================
+ Hits        22154    35798    +13644     
- Misses      24738    25610      +872     

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