Support newer versions of objdump

[petrhosek]

Resolved incompatibilities with newer versions of objdump. The most significant change seems to be the newly introduced behaviour where objdump interprets arbitrary long sequences of 0x66 bytes as data32 annotations. However, this does not seem to be valid according to the AMD manual nor gcc. To allow crosschecking against newer versions, the cross-checking scripts strips out these annotations.

Alternatively, we could extend the validator to output data32 annotations, but in that case we would have to perform some post-processing as well i.e. strip them or replace them with .byte 0x66 in the input which is being fed to gcc during cross-check.