Replace the ClassExpression const& reference in the NewClass
instruction with a u32 class_blueprint_index. The interpreter now
reads from the ClassBlueprint stored on the Executable and calls
construct_class() instead of the AST-based create_class_constructor().
Literal field initializers (numbers, booleans, null, strings, negated
numbers) are used directly in construct_class() without creating an
ECMAScriptFunctionObject, avoiding function creation overhead for
common field patterns like `x = 0` or `name = "hello"`.
Set class_field_initializer_name on SharedFunctionInstanceData at
codegen time for statically-known field keys (identifiers, private
identifiers, string literals, and numeric literals). For computed
keys, the name is set at runtime in construct_class().
ClassExpression AST nodes are no longer referenced from bytecode.
Add a standalone construct_class() function that builds a class from
a ClassBlueprint and an Executable, replacing the virtual dispatch
through ClassElement::class_element_evaluation() with a direct switch
on ClassElementDescriptor::Kind.
This function reads pre-compiled SharedFunctionInstanceData indices
from the blueprint, creates ECMAScriptFunctionObjects at runtime, and
handles all class element types: methods, getters, setters, fields
(with initializers), and static initializers.
The function exists but is not yet called. No behavioral change.
