[lldb/crashlog] Adapt raw text crashlog exception to json format

This patch parses CrashLog exception data from the raw
text format and adapts it to the new JSON format.

This is necessary for feature parity between the 2 formats.

Differential Revision: https://reviews.llvm.org/D131719



Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>