v8_libsampler was previously split off to serve goals that were never
achieved and seem unlikely to be. Since the division creates a
dependency cycle between v8_base_without_compiler and v8_libsampler
(where one edge is a #include that breaks gn check), this moves
sampler.* back into v8_base_without_compiler and removes the
v8_libsampler target.

Bug: v8:7330
Change-Id: Ied87b68927a372ec084cd650b278af98d7db5f8e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2727818
Auto-Submit: Dan Elphick <delphick@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73108}