Add a missing check to reject illegal sections.

The test is added in three forms, to give fuzzers more food: A fuzzer
regression test for the streaming fuzzer, a unit test for the streaming
decoder, and an mjsunit test for streaming compilation.

Drive-by: Remove a redundant line in the synchronous decoder (this is
already handled by the following statement.

R=ahaas@chromium.org

Bug: chromium:1335023
Change-Id: Ic8c3b301f1b58981c7d68eafcffc89531ed2c64c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3698549Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81071}