src: remove preview for heap dump utilities

At least `createHeapSnapshotStream()` and `triggerHeapSnapshot()`
do have side effects, and more importantly, they should not be
run transparently. Without this, typing e.g. `v8.getHeapSnapshot()`
into the REPL will result in a crash or infinite loop while the REPL
evaluates the expression for a preview.

PR-URL: https://github.com/nodejs/node/pull/31570


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>