REPL 'let' declared variables use VariableLocation::REPL_GLOBAL which
was not handled by a switch in the bytecode generator. The default
case ran into an UNREACHABLE.

This CL fixes this by properly handling VariableLocation::REPL_GLOBAL
for delete.

Drive-by: Replaced the default case with an explicit case for
VariableLocation::MODULE.

Bug: chromium:1052721
Change-Id: I1330ff2f2c6f042a596a8298599a5d58769894f3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2060488
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66301}