This aligns the breakpoint behavior of YieldExpression and
AwaitExpression with the behavior of AssignmentExpression
in V8. It basically boils down to not reporting expression
positions on SuspendGenerator bytecodes as breakable
locations.

In particular the initial implicit yield of any generator
function is no longer a breakable position. In light of
this changes we also refine https://crrev.com/c/2949099
to not be able to step to the initial implicit yield
either, which would otherwise be really odd.

Before: https://imgur.com/KYy9F1S.png
After: https://imgur.com/gCnWU8J.png
Doc: https://goo.gle/devtools-reliable-await-breakpoints
Bug: chromium:901814, chromium:1319019, chromium:1246869
Fixed: chromium:1319019, chromium:1357501
Change-Id: I0c5f83e279918eb392d8f77a8a04c4c0285f938e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3909688
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Kim-Anh Tran <kimanh@chromium.org>
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83392}