add strfmt.c for printf base function in ktap script
make printf free its temp buffer
remove mutex lock in print function

print maybe called in interrupt contex, so there will deadlock
if using mutex, just remove it.
add todo comments for tstring_dump function
add localgc field of per ktap thread

All annotate string will be deleted when ktap tracing
thread exit, printf generated tstring is also chaining into
localgc, this will reduct memory overhead when annotate printf
heave used.(we might improve this more by indicate printf when
annotate string is in format string)

More: protect tstring allocation by spinlock
(one issue: tstring lookup conflict with resizing?)