Sparc: fix exceptions in delay slot

Sparc: fix exceptions in delay slot

Fix a case where an exception happens with the
instruction in the delay slot.

Recovery of branch condition in the exception handling
code was not converted to TCG. Because the condition
was bogus, wrong NPC could be selected from the two
candidates.

A nice bug report with a test case can be found in:
https://bugs.launchpad.net/qemu/+bug/551814

Fix based on patch by Fabrice Bellard.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>