dtrace: Use deterministic temp file creation for all temp files
`dtrace -G -C` creates temporary files with random filenames. The name
of these temporary files gets embedded in the ELF `.symtab` of the final
object files, making them always slightly different.
This behavior makes all packages that use `dtrace`-produced object files
inherently non reproducible.
To fix this issue all temporary files are now created using
the same deterministic procedure currently used only for the
temporary "c." files.