V8 doesn't like having internal slots on the "real" globalThis object.
This commit works around this limitation by storing the inner globalThis
objects for segregated globals in a context slot.
Code run within Deno-mode and Node-mode should have access to a
slightly different set of globals. Previously this was done through a
compile time code-transform for Node-mode, but this is not ideal and has
many edge cases, for example Node's globalThis having a different
identity than Deno's globalThis.
This commit makes the `globalThis` of the entire runtime a semi-proxy.
This proxy returns a different set of globals depending on the caller's
mode. This is not a full proxy, because it is shadowed by "real"
properties on globalThis. This is done to avoid the overhead of a full
proxy for all globalThis operations.
The globals between Deno-mode and Node-mode are now properly segregated.
This means that code running in Deno-mode will not have access to Node's
globals, and vice versa. Deleting a managed global in Deno-mode will
NOT delete the corresponding global in Node-mode, and vice versa.
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Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>
Co-authored-by: Aapo Alasuutari <aapo.alasuutari@gmail.com>
