feat(grpc-tools): add omit_serialize_instanceof generator option

[lionello]

Fixes #2865

This adds a new flag omit_serialize_instanceof which, when set, omits the instanceof check from the generated JS code. It defaults to false, which retains the current behavior (ie. with the check).

[linux-foundation-easycla]

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• ✅ login: lionello / name: Lio李歐 (0a20c2d)

[murgatroid99]

The only difference between the separate serialize_* functions is the instanceof check, so with this option set, the generator should instead generate a single serialize method that is used for serializing every message type.

[lionello]

The only difference between the separate serialize_* functions is the instanceof check, so with this option set, the generator should instead generate a single serialize method that is used for serializing every message type.

@murgatroid99 I looked into this, and it's certainly possible to fix, but it adds a lot of complexity for little gain. It also no longer allows putting breakpoints on a particular instance of the serialize_* function during debugging, which is something I've done before, so IMHO it's not worth the effort. Unless you tell me it's a requirement to get this merged, I'd vote to merge this as-is.

[lionello]

Tests appear to be failing with

FATAL ERROR: MarkCompactCollector: young object promotion failed Allocation failed - JavaScript heap out of memory

and

  1) Name Resolver DNS Names Should resolve a public address:
     Error: Timeout of 4000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
      at listOnTimeout (node:internal/timers:559:17)
      at processTimers (node:internal/timers:502:7)

[murgatroid99]

Ignore those failures. They're not related to this change.