target/sh4: get rid of DELAY_SLOT_CLEARME

target/sh4: get rid of DELAY_SLOT_CLEARME

Now that ctx->flags has been split, it becomes clear that
DELAY_SLOT_CLEARME has not impact on the code generation: in both case
ctx->envflags is cleared, either by clearing all the flags, or by
setting it to 0. This is left-over from pre-TCG era.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>