This reverts commit 4dc1fb4e.

Reason for revert: the regression from the original change was likely due to unlucky factors like code alignment.

Original change's description:
> Revert "[torque] Support bitfield structs stored within Smis"
>
> This reverts commit e5e4ea96.
>
> Reason for revert: mysterious performance regression chromium:1052756
>
> Original change's description:
> > [torque] Support bitfield structs stored within Smis
> >
> > This change moves the definition of the bits stored in DebugInfo::flags
> > to Torque, and updates the only Torque usage of that field to use more
> > natural syntax. This is intended as an example of common patterns found
> > in various other classes. Several supporting changes are required:
> >
> > 1. Add a new type representing a bitfield struct stored within a Smi. It
> >    is currently called SmiTagged, but I'm open to suggestions.
> > 2. Add an enum-style output for Torque bitfield structs whose bitfields
> >    occupy only one bit each.
> > 3. Add a new case to MachineOperatorReducer that makes the generated
> >    code for IncBlockCounter match with what was generated before this
> >    change.
> > 4. Add support for reporting these bitfields in the postmortem debugging
> >    API. The format matches existing bitfields but with an offset value
> >    that includes the SMI shift size.
> >
> > Bug: v8:7793
> > Change-Id: Icaecbe4a162da55d2d9a3a35a8ea85b285b2f1b7
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2028832
> > Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> > Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> > Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#66182}
>
> Bug: chromium:1052756, v8:7793
> Change-Id: I9e2897efbb6321124bf4952cf09de2f179f7310d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2062569
> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#66349}

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:1052756, v8:7793
Change-Id: I6087928aa14c8551ebd294513bd8d6ffa402a0d4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2070635Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#66465}