We had a test which first enabled the profiler, and then compiled wasm
code. In this case, all code objects were registered correctly and the
profile looked as expected.
This CL extends the test for also test another order: First compile the
wasm code, then enable the profiler. In that case, we were reporting a
wrong debug name of the exported wasm function. The name of that
function is spec'ed to be the string representation of the function
index. But for debugging, we want to see a more meaningful name,
identical to the name we show when reporting the code during
compilation.

This fix requires handlifying the {SharedFunctionInfo::DebugName}
method, because for exported wasm functions, it needs to allocate a new
name on the JS heap.
In order to avoid this allocation where possible, a second variant is
added which returns a unique_ptr directly. This can be used in all
places where the name is just being printed, which turned out to be the
majority of cases ({DebugName().ToCString()}).

R=petermarshall@chromium.org

Bug: chromium:1141787
Change-Id: I0343c2f06f0b852007535ff07459b712801ead01
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2543931
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71308}