Fix setjmp/longjump usage in JPEG error handling

Pushes and pops nested jmp_bufs in a stack for proper handling of
nested setjmp calls. Ensures longjmp is never called to a stack frame
that has exited.

Bug: skia:
Change-Id: I18d62504f6e5e3eb53026c3b48617b92ea74b905
Reviewed-on: https://skia-review.googlesource.com/79241
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
7 files changed