This is the same test as ecdsa-prime256v1-sha512.pem, however the SIGNATURE has
been changed to a (valid) BIT STRING containing two unused bits.

Note that the last two bits of the original signature were 0, so the
DER-encoded bytes portion of the mutated BIT STRING remains the same. All that
changes is the octet at the start which indicates the number of unused bits.

In other words SIGNATURE changes from:
  03 47 00 30 ... 84
To:
  03 47 02 30 ... 84


-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEnLDPaTA9r8dh1ORoe07PA55tNKuWSvgIENjVWKS
o1vctUSM6F4iSCobuCKGWLHnvoxf7eHnil9rSFG25lfoceA==
-----END PUBLIC KEY-----

$ openssl asn1parse -i < [PUBLIC KEY]
    0:d=0  hl=2 l=  89 cons: SEQUENCE          
    2:d=1  hl=2 l=  19 cons:  SEQUENCE          
    4:d=2  hl=2 l=   7 prim:   OBJECT            :id-ecPublicKey
   13:d=2  hl=2 l=   8 prim:   OBJECT            :prime256v1
   23:d=1  hl=2 l=  66 prim:  BIT STRING        


-----BEGIN ALGORITHM-----
MAoGCCqGSM49BAME
-----END ALGORITHM-----

$ openssl asn1parse -i < [ALGORITHM]
    0:d=0  hl=2 l=  10 cons: SEQUENCE          
    2:d=1  hl=2 l=   8 prim:  OBJECT            :ecdsa-with-SHA512


-----BEGIN DATA-----
bikyFTMBpO72gOZCiSmtrpiMEI1mijH/VdBImUfXX/gaRr+J6E1kAfAjvm6HaI+814TXhcqEZzV
SSstS0ARSyEBApHnnzDMJNkQdk7vnIqlDKm4dsRK1yUA7ECcssTR/1hnUY/ep0iOtdv3gbYpog1
APuEMjWr/5jiQb37VTjD4=
-----END DATA-----


-----BEGIN SIGNATURE-----
A0cCMEQCIEufkeQoUocmGh0ckjz2Gc1SwXXP5/G+YKUljGEDSLo9AiAoxF+QHXHEGymGOOwNaoX
X/LDDO7/sWpyBCEa2OSiahA==
-----END SIGNATURE-----

$ openssl asn1parse -i < [SIGNATURE]
    0:d=0  hl=2 l=  71 prim: BIT STRING