single argument panic

note that sortmain.go has been run through hg gofmt;
only the formatting of the day initializers changed.
i'm happy to revert that formatting if you'd prefer.

stop on error in doc/progs/run

R=r
CC=golang-dev
https://golang.org/cl/850041
diff --git a/test/mallocrep.go b/test/mallocrep.go
index e7f3f06..2357d83 100644
--- a/test/mallocrep.go
+++ b/test/mallocrep.go
@@ -47,7 +47,8 @@
 			during := runtime.MemStats.Alloc
 			runtime.Free(b)
 			if a := runtime.MemStats.Alloc; a != 0 {
-				panic("allocated ", j, ": wrong stats: during=", during, " after=", a, " (want 0)")
+				println("allocated ", j, ": wrong stats: during=", during, " after=", a, " (want 0)")
+				panic("fail")
 			}
 			bigger()
 		}