This is a reland of c594a20e

Moved the getters to the .cc file to avoid link problems as they
are not performance critical anyway.

Moved ProfileNode::source_type to cc as it uses the _entry() functions
which are no longer inline.

Original change's description:
> [cpu-profiler] Use base::LeakyObject for static CodeEntry objects
>
> This is preferred over the older LazyInstance based stuff, and has
> a lot less boilerplate and is easier to follow.
>
> Bug: v8:8600
> Change-Id: I7c5c5ae04c064b0fc598dc01f1ed5442dc21a17b
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2640475
> Commit-Queue: Peter Marshall <petermarshall@chromium.org>
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#72224}

Bug: v8:8600
Cq-Include-Trybots: luci.v8.try:v8_linux64_ubsan_rel_ng
Change-Id: I0ad9118e6d3bd087707609714b20aee1cbc4f459
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2642252
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72254}