JAZZ Piano Singerscq Blues ''Women Accompany Themselves.'' Rosetta Records RR 1303 . Yet another collection of fine singers, this time accompanying themselves at the piano, and showing themselves to be equally accomplished at the keyboard. This is a delightful and varied set, ranging from Gladys Bentley and her vocal ''trumpet growls'' on her own tune, ''Worried Blues,'' (1928) to blind singer and barrelhouse pianist Arizona Dranes, who brought her church background and gospel feel to ''Lamb's Blood Has Washed Me Clean'' (1926). Others featured here are Julia Lee, Hazel Scott, Victoria Spivey, and Lil Armstrong. Most of these women sing and play the blues, with that same gutsy and upbeat feel of the previous two albums, with one exception: Hadda Brooks, who does a heartfelt version of Ray Noble's pretty ballad ''I Hadn't Anyone 'Til You'' (1950).