This extends the debug side table to also store register locations in
addition to constants and stack values.
Previously, every value that was not constant was assumed to be spilled
to the stack. This made sense, because without breakpoints we would only
emit debug side table entries at call sites, where all registers are
spilled.
With breakpoints, this changes. At break locations, values might be live
in registers.

The logic to decide whether a value will live in the register or on the
stack is extended, because we sometimes generate the debug side table
entry at a point where the registers are not spilled yet. The debug side
table entry creation needs to account for that, and assume that these
registers will still be spilled.

R=thibaudm@chromium.org

Bug: v8:10147, v8:10222
Change-Id: I3b020dfaa29fc007047663706ee286180a996bfd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2066960
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66407}