There were a couple of ways that libgccjit could fail to unlink all
of its tempfiles, leading to /tmp/libgccjit-* tempdirs lingering
after the build:
- dumpfiles requested by gcc_jit_context_enable_dump
- ahead-of-time compilation artifacts which lingered in the tempdir
  after they've been copied up to the output_path.  This was only
  the case for GCC_JIT_OUTPUT_KIND_OBJECT_FILE and
  GCC_JIT_OUTPUT_KIND_EXECUTABLE.

The following patch fixes these by introducing a vec of additional
cleanups to be performed by gcc:jit::tempdir's dtor.

In addition, if a gcc_jit_result * is leaked and
GCC_JIT_BOOL_OPTION_DEBUGINFO is enabled, the tempdir will also
not be cleaned up.  This was the case for tut04-toyvm/toyvm.cc
which the patch fixes by introducing a wrapper around
gcc_jit_result *.  Doing this required some updates to the
corresponding docs.

gcc/jit/ChangeLog:
	PR jit/69144
	* jit-playback.c (gcc::jit::playback::compile_to_file::postprocess):
	Potentially add the temporary artifact to the tempdir's list of
	tempfiles needing additional cleanup.
	(gcc::jit::playback::context::extract_any_requested_dumps): Likewise
	for the dumpfile.
	* jit-tempdir.c (gcc::jit::tempdir::~tempdir): Clean up additional
	tempfiles.
	* jit-tempdir.h (gcc::jit::tempdir::add_temp_file): New method.
	(gcc::jit::tempdir::m_tempfiles): New field.
	* docs/cp/intro/tutorial04.rst: Update for changes to toyvm.cc.
	* docs/examples/tut04-toyvm/toyvm.cc (class compilation_result):
	New.
	(toyvm_function::compile): Change return type from function ptr
	to a compilation_result.
	(toyvm_function::get_function_name): New accessor.
	(toyvm_function::m_funcname): New field.
	(get_function_name): Convert to...
	(toyvm_function::make_function_name): ...this new method.
	(toyvm_function::parse): Call make_function_name.
	(toyvm_function::compile): Convert return type from function ptr
	to a compilation_result.  Use get_function_name.
	(compilation_state::compile): Convert return type from
	gcc_jit_result * to a compilation_result.
	(test_script): Update for above changes, extracting the code from
	the compilation_result.
	(main): Likewise.
	* docs/_build/texinfo/libgccjit.texi: Regenerate.

From-SVN: r232582