build: fix inspector dependency resolution

It was reported that parallel builds on Windows sometimes error because
of missing intermediate files.

On closer inspection I noticed that some files are copied from src/ to
the intermediate build directory in a way where they don't participate
in dependency resolution. Put another way, the build system doesn't
know to wait for the copy to complete because we don't tell it to.

Fix that by not copying around files but instead making the script that
processes them a little smarter about where to find them and where to
store the results.

PR-URL: https://github.com/nodejs/node/pull/27026
Fixes: https://github.com/nodejs/node/issues/27025


Reviewed-By: Eugene Ostroukhov <eostroukhov@google.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Signed-off-by: Beth Griggs <Bethany.Griggs@uk.ibm.com>