Three go/parser, go/doc and testing proposals open

Three proposals open at once: a deprecated ResolveFile shim for go/parser, a way to recover ast.Ident import paths from go/doc, and Damien Neild's pitch to let testing accept examples with any signature. The testing one is the most interesting of the three, since it reopens a thread that has been bouncing between issues 21111 and 64993 for a while. On the discussion side, a writeup walks through chasing a Go optimization that pprof initially claimed did nothing, eventually tracking it to a 0x0 terminal bug and a 12x throughput win. A solid pprof tutorial dressed up as a debugging story.