debugger: fix warning format-overflow= '%s' directive arg is null

Change-Id: Iba00fbcc3f8fde088bed62b93c4e3acae4e0b902
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4777
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>

Debugger: Fix oversight.

DebugReportGenerator:
- In the case where the function was already disassembled beforehand,
we weren't retrieving the statement, leading to a null pointer
dereference.

Debugger: Rework parts of report generation.

Team:
- Adjust report generation event to include a final status code for listeners.

CliContext,TeamWindow,ReportUserinterface:
- Use aforementioned status code to indicate whether report generation
succeeded or failed.

DebugReportGenerator:
- Notify listeners if report generation fails. This may have previously
been responsible for some bug reports where it was indicated that the
debugger hung without exiting after being asked to save a report from
a crashed app.
- When dumping disassembly, retrieve it directly if necessary rather than
requesting it via the user interface listener. This also fixes the quirk
that requesting to save a crash report while looking at the source code
of a function would trigger switching it to disassembly visually.
- When walking the list of threads to dump, acquire references to all of
them before starting. Otherwise, it was potentially possible for a running
but not crashed thread to exit while we were generating the report, leaving
us with a pointer to a deleted thread. This was most likely the cause of one
of the crashes reported in #13082.
- When receiving the notification that source code state has changed, clear
the waiting function. Otherwise, it was potentially possible for us to get
other state change notifications, leading to the data semaphore being
released too often. This would then cause later potential waits such as
the stack frame memory dump to not actually wait when they should,
potentially leading them to dereference objects that weren't yet ready.
This fixes another of the crashes in #13802.

Debugger: Adjustments to report generator.

DebugReportGenerator:
- Due to the changes made with respect to correctly handling switching to
disassembly explicitly, the report generator needs to request loading
source files as it walks the stack trace in order to get source-based
line number information. Fixes crash reports having -1 as the line number
in cases where debug information was available, but the user hadn't yet
looked at the source file in question.

LoadSourceCodeJob:
- Cleanup.

Debugger: Split into core library and application.

- Add subfolder src/kits/debugger which contains the debugger's core
functionality and lower layers. Correspondingly add headers/private/debugger
for shared headers to be used by clients such as the Debugger application
and eventual remote_debug_server. Adjust various files to account for
differences as a result of the split and moves.
- Add libdebugger.so to minimal Jamfile.