Replace the old indentation-based AST dump with a new tree-drawing
approach using unicode box characters. Each node now also shows its
source position as @line:column, and additional internal state:
- Identifier: [argument:N] vs [variable:N], declaration kind
(var/let/const), [global], [in-eval-scope]
- FunctionNode: [strict], [arrow], [direct-eval], [uses-this],
[uses-this-from-environment], [might-need-arguments]
- Program: (script)/(module), [strict], [top-level-await]
- YieldExpression: [yield*] for delegation
Dump code is moved from AST.cpp into a new ASTDump.cpp file.
