playbooks: Unify test setup for system & unit tests

There is no significant benefit in keeping this configuration separated.
Now the to-be installed packages are tracked in a single place and the
test playbooks only call the relevant tests.

This was pointed out by in 6063eb27b9

https://github.com/containers/toolbox/pull/898

.zuul.yaml

@@ -7,6 +7,7 @@
       nodes:
         - name: ci-node-33
           label: cloud-fedora-33-small
+    pre-run: playbooks/setup-env.yaml
     run: playbooks/unit-test.yaml
 
 - job:

playbooks/setup-env.yaml

@@ -40,3 +40,21 @@
 
     - name: Show podman debug information
       command: podman info --debug
+
+    - name: Set up build directory
+      command: meson builddir
+      args:
+        chdir: '{{ zuul.project.src_dir }}'
+
+    - name: Build Toolbox
+      command: ninja -C builddir
+      args:
+        chdir: '{{ zuul.project.src_dir }}'
+        creates: builddir/src/toolbox
+
+    - name: Install Toolbox
+      become: yes
+      command: ninja -C builddir install
+      args:
+        chdir: '{{ zuul.project.src_dir }}'
+        creates: /usr/local/bin/toolbox

playbooks/system-test.yaml

@@ -1,32 +1,10 @@
 ---
 - hosts: all
-
-  vars:
-    toolbox_bin: '/usr/local/bin/toolbox'
-
   tasks:
-    - name: Set up build directory
-      command: meson builddir
-      args:
-        chdir: '{{ zuul.project.src_dir }}'
-
-    - name: Build Toolbox
-      command: ninja -C builddir
-      args:
-        chdir: '{{ zuul.project.src_dir }}'
-        creates: builddir/src/toolbox
-
-    - name: Install Toolbox
-      become: yes
-      command: ninja -C builddir install
-      args:
-        chdir: '{{ zuul.project.src_dir }}'
-        creates: '{{ toolbox_bin }}'
-
     - name: Run system tests
       command: bats --timing ./test/system
       environment:
         PODMAN: '/usr/bin/podman'
-        TOOLBOX: '{{ toolbox_bin }}'
+        TOOLBOX: '/usr/local/bin/toolbox'
       args:
         chdir: '{{ zuul.project.src_dir }}'

playbooks/unit-test.yaml

@@ -1,27 +1,6 @@
 ---
 - hosts: all
   tasks:
-    - name: Install requirements
-      become: yes
-      package:
-        name:
-          - golang
-          - golang-github-cpuguy83-md2man
-          - ninja-build
-          - meson
-          - ShellCheck
-
-    - name: Set up build directory
-      command: meson builddir
-      args:
-        chdir: '{{ zuul.project.src_dir }}'
-
-    - name: Build Toolbox
-      command: ninja -C builddir
-      args:
-        chdir: '{{ zuul.project.src_dir }}'
-        creates: builddir/src/toolbox
-
     - name: Test
       command: ninja -C builddir test
       args: