target/sparc: Introduce DYNAMIC_PC_LOOKUP

target/sparc: Introduce DYNAMIC_PC_LOOKUP

Create a new artificial "next pc" which also indicates
that nothing has changed within the cpu state which
requires returning to the main loop.

Pipe this new value though all pc/npc checks.
Do not produce this new value yet.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230628071202.230991-5-richard.henderson@linaro.org>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>