SBA PCA not covered by coverage tests

The PCA functionality within the SBA format is poorly covered by the automatic tests, see:

• https://ivas-codec-pc.3gpp.org/ivas-codec/coverage/lib_enc/ivas_pca_enc.c.gcov.html
• https://ivas-codec-pc.3gpp.org/ivas-codec/coverage/lib_dec/ivas_pca_dec.c.gcov.html
• https://ivas-codec-pc.3gpp.org/ivas-codec/coverage/lib_com/ivas_pca_tools.c.gcov.html

It is thus proposed to add a self-test condition to cover it.