target/sh4: fix TCG leak during gusa sequence

This fixes bug #1735384 while running java under qemu-sh4. When debug
was enabled it showed a problem with TCG temps. Once fixed I was able
to run java -version normally.

Cc: qemu-stable@nongnu.org
Reported-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20171206093050.25308-1-alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
