[Sema] Emit diagnostics for uncorrected delayed typos at the end of TU
Instead of asserting all typos are corrected in the sema destructor.
The sema destructor is not run in the common case of running the compiler
with the -disable-free cc1 flag (which is the default in the driver).
Having this assertion led to crashes in libclang and clangd, which are not
reproducible when running the compiler.
Asserting at the end of the TU could be an option, but finding all
missing typo correction cases is hard and having worse diagnostics instead
of a failing assertion is a better trade-off.
For more discussion on this, see:
Reviewers: sammccall, rsmith
Reviewed By: rsmith
Subscribers: usaxena95, dgoldman, jkorous, vsapsai, rnk, kadircet, cfe-commits
Differential Revision: https://reviews.llvm.org/D64799