Fix, and optimize, miniperf-record kernel map synthesis.

1. Parsing kallsyms is too slow; it takes hundreds of ms on unagi.  CPU
scaling is probaboly not helping, but even so it's expensive.  Instead,
read /proc/modules and use the (hopefully) first line of kallsyms to find
the kernel start.

2. The modules may not be in address order in kallsyms (or modules), so
this wasn't even correct.  qsort is a little ugly, but it's reasonably
fire-and-forget.
Recognize some options to miniperf-record.

The most important option is -e (or at least the obvious cases of it)
and the attending -c and -F; -o is also important.  A goal is partial
compatibility with actual perf-record; i.e., if a flag is recognized by
both, it will mean approximately the same thing.
Enlarge miniperf-record's output buffer