http: use runtime/debug.Stack() to dump stack trace on panic. Test output now looks like this:
http: use runtime/debug.Stack() to dump stack trace on panic.
Test output now looks like this:

2011/06/15 21:10:41 http: panic serving 127.0.0.1:59729: intentional death for testing
$GOROOT/src/pkg/http/server.go:495 (0x3f9f8)
        _func_004: buf.Write(debug.Stack())
$GOROOT/src/pkg/runtime/proc.c:1041 (0x12367)
        panic: reflect·call(d->fn, d->args, d->siz);
$GOROOT/src/pkg/http/serve_test.go:775 (0x5831b)
        _func_029: panic("intentional death for testing")
$GOROOT/src/pkg/http/server.go:575 (0x26366)
        HandlerFunc.ServeHTTP: f(w, r)
$GOROOT/src/pkg/http/server.go:541 (0x261a9)
        *conn.serve: c.handler.ServeHTTP(w, w.req)
$GOROOT/src/pkg/runtime/proc.c:178 (0x10a83)
        goexit: runtime·goexit(void)

with $GOROOT expanded, of course.

R=bradfitz, rsc
CC=golang-dev
http://codereview.appspot.com/4607051
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go