tests/docker: Add flex/bison to debian-hexagon-cross

debian-hexagon-cross contains two images, one to build the toolchain
used for building the Hexagon tests themselves, and one image to build
QEMU and run the tests.

This commit adds flex/bison to the final image that builds QEMU so that
it can also build idef-parser.

Note: This container is not built by the CI and needs to be rebuilt and
updated manually.

Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20221014223642.147845-1-anjo@rev.ng>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20221027183637.2772968-8-alex.bennee@linaro.org>

tests/docker/dockerfiles/debian-hexagon-cross.docker

@@ -43,7 +43,7 @@ RUN cat /etc/apt/sources.list | sed "s/^deb\ /deb-src /" >> /etc/apt/sources.lis
 # Install QEMU build deps for use in CI
 RUN apt update && \
     DEBIAN_FRONTEND=noninteractive apt install -yy eatmydata && \
-    DEBIAN_FRONTEND=noninteractive eatmydata apt install -yy git ninja-build && \
+    DEBIAN_FRONTEND=noninteractive eatmydata apt install -yy bison flex git ninja-build && \
     DEBIAN_FRONTEND=noninteractive eatmydata \
     apt build-dep -yy --arch-only qemu
 COPY --from=0 /usr/local /usr/local