reduce FreeBSD CI build matrix and disable WAV check

We seem to run into problems with too much CPU usage for the GitHub
Actions: Some builds hang forever during the (currently disabled)
check_plugout_wav.sh check or don't start at all (hanging while
waiting for an IP during the FreeBSD boot).

I'm on a free plan and 1 Mac runner CPU second is worth 10 Linux
runner CPU seconds, so reduce the FreeBSD testing from 4 to 1 matrix
combinations and only keep a Linux based one.

The WAV check is also disabled, as it will use some CPU for rendering
the WAV files.

.github/workflows/build_freebsd.yml

@@ -18,15 +18,16 @@ jobs:
     strategy:
       matrix:
         os:
-          - name: freebsd
-            architecture: x86-64
-            version: '13.2'
-            host: macos-12
+#          - name: freebsd
+#            architecture: x86-64
+#            version: '13.2'
+#            host: macos-12
           - name: freebsd
             architecture: arm64
             version: '13.2'
             host: ubuntu-latest
-        flags: ['', '--enable-sharedlibgbs']
+        flags: ['']
+#        flags: ['', '--enable-sharedlibgbs']
 
     steps:
       - uses: actions/checkout@v4
@@ -46,7 +47,7 @@ jobs:
           run: |
             yes | sudo pkg install gmake
             gmake
-            ./check_plugout_wav.sh
+            ## ./check_plugout_wav.sh
       - name: Check activated plugouts
         run: |
           ./check_plugouts.sh devdsp wav