Why I want to fix this: I got a CL to replace V8_NORETURN by
[[noreturn]], but clang-format formats this as
  extern "C"[[noreturn]] PRINT_FORMAT...
(i.e. missing whitespace).
Also, this is the only extern "C" function in our code base, so if we
do not need to call it from C, we should just get rid of it.

R=jochen@chromium.org
BUG=v8:6474

Change-Id: I950bdc505822eb37a107c58e63c82a61907ba515
Reviewed-on: https://chromium-review.googlesource.com/539341Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46149}