Allow DOF sections with excessively long probe function components.

Without this change, DTrace will refuse to load a DOF section if the
function component of any of its probes exceeds DTRACE_FUNCNAMELEN (128).
Probes in C++ programs can have very long function components. Rather than
rejecting all probes if a single probe exceeds the limit, simply skip the
invalid probe and emit a warning. This ensures that valid probes are
instantiated.

PR: 207735
MFC after: 2 weeks