[analyzer][ctu] Avoid parsing invocation list again and again during on-demand parsing of CTU

During CTU, the *on-demand parsing* will read and parse the invocation
list to know how to compile the file being imported. However, it seems
that the invocation list will be parsed again if a previous parsing
has failed.
Then, parse again and fail again. This patch tries to overcome the
problem by storing the error code during the first parsing, and
re-create the stored error during the later parsings.

Reviewed By: steakhal

Patch By: OikawaKirie!

Differential Revision: https://reviews.llvm.org/D101763