Testing total space fails for gccgo when not using split
stacks, because then each goroutine has a large stack, and so
the total memory usage is large.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5487068
Revert workaround in compiler and
revert test for compiler workaround.
Tested that the 386 build continues to fail if
the gc change is made without the reflect change.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5312041
The work buffer management used by the garbage
collector during parallel collections leaks buffers.
This CL tests for and fixes the leak.
R=golang-dev, dvyukov, r
CC=golang-dev
https://golang.org/cl/5254059
