Use newer GCC to fix failed builds on 11.7/11.8

Bumped to GCC 9.31 via devtoolset-9-gcc-c++ devtoolset-9-gcc
packages from centos-release-scl repository.
Tested locally 10.6 - 11.8.

The reason behind source /opt/rh/devtoolset-9/enable is that
devtools require PATH alteration in order to set-up the environment
for the newer GCC.

Added COMPILER_LAUNCHER=ccache so that CCACHE is used
effectively with the newer GCC.

To inspect what was modified in the centos-7-bintar container image
please see the Dockerfile in the changelog directory.

$ docker run --rm quay.io/mariadb-foundation/bb-worker:dev_centos7-bintar-gcc ls -l /changelog
total 14484
-rw-rw-r-- 1 root root 14825969 Jan 15 18:16 2021-04-28-gnutlsa-centos74-amd64.tar.bz2
-rw-rw-r-- 1 root root     1313 Jan 17 11:42 Dockerfile

I am still waiting on Serg/Elena reply to see if this is a convenient solution
to solve building 11.7/11.8 bintars.

master-docker-nonstandard/master.cfg

@@ -1347,7 +1347,15 @@ f_bintar.addStep(
             "sh",
             "-c",
             util.Interpolate(
-                'cmake . -DWITH_READLINE=1 -DCURSES_NEED_NCURSES=1 -DBUILD_CONFIG=mysql_release -DWITH_SSL=bundled -DPLATFORM=linux-systemd && make -j%(kw:jobs)s package',
+                """source /opt/rh/devtoolset-9/enable && cmake . \\
+                    -DWITH_READLINE=1 \\
+                    -DCURSES_NEED_NCURSES=1 \\
+                    -DBUILD_CONFIG=mysql_release \\
+                    -DCMAKE_C_COMPILER_LAUNCHER=ccache \\
+                    -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \\
+                    -DWITH_SSL=bundled \\
+                    -DPLATFORM=linux-systemd \\
+                    && make -j%(kw:jobs)s package""",
                 perf_schema=util.Property("perf_schema", default="YES"),
                 build_type=util.Property("build_type", default="RelWithDebInfo"),
                 jobs=util.Property("jobs", default="$(getconf _NPROCESSORS_ONLN)"),