Refactor ast function types

[raskad]

Depends on #3917

This PR refactors the way we represent functions and classes in our AST to decrease ambiguities. It also refactors the way we parse named named executions of anonymous functions, reducing the complexity in the parser and aligning the handling more with the spec.

These are the changes:

• Refactor handling of anonymous function names
  • Remove pass trough of names in parser
  • Set anonymous function names if needed while parsing assignment expressions etc.
• Split AST nodes
  • Function -> FunctionExpression and FunctionDeclaration
  • AsyncFunction -> AsyncFunctionExpression and AsyncFunctionDeclaration
  • Generator -> GeneratorExpression and GeneratorDeclaration
  • AsyncGenerator -> AsyncGeneratorExpression and AsyncGeneratorDeclaration
  • Class -> ClassExpression and ClassDeclaration
• Refactor object literal and class methods into ObjectMethodDefinition and ClassMethodDefinition
• Fix class field computed names for functions and add tests

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	48,212	48,212	0
Passed	43,264	43,264	0
Ignored	1,413	1,413	0
Failed	3,535	3,535	0
Panics	0	0	0
Conformance	89.74%	89.74%	0.00%

[HalidOdat]

Nice work! Looks good to me! :)

[jedel1043]

Looks great! Always happy to move invariants from execution to compile time :)