This change updates CachedTemplateObjectMap, BreakPointInfo, and
BreakPoint to inherit directly from Struct rather than Tuple2 or Tuple3.
It also removes Tuple3 because nothing else used Tuple3. By avoiding
tuple types, we get various benefits that Torque can provide:
- stricter debug verifier functions
- accessors, cast functions, and printers are generated
- BreakPoint and BreakPointInfo have different instance types, so you
  can tell them apart at runtime or in a debugger

Change-Id: I9367bc08c6dea55d659fd610f9f6105fd61c907a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1988793Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#65668}