runtime/pprof: disable new memory test

It cannot run 'go tool pprof'. There is no guarantee that's installed.
It needs to build a temporary pprof binary and run that.
It also needs to skip the test on systems that can't build and
run binaries, namely android and nacl.

See src/cmd/nm/nm_test.go's TestNM for a template.

Update #8867
Status: Accepted

TBR=dvyukov
CC=golang-codereviews
https://golang.org/cl/153710043

src/runtime/malloc.go

@@ -40,6 +40,8 @@ type pageID uintptr
 // base address for all 0-byte allocations
 var zerobase uintptr
 
+//go:nowritebarrier
+
 // Allocate an object of size bytes.
 // Small objects are allocated from the per-P cache's free lists.
 // Large objects (> 32 kB) are allocated straight from the heap.

src/runtime/pprof/mprof_test.go

@@ -52,6 +52,7 @@ func allocatePersistent1K() {
 var memoryProfilerRun = 0
 
 func TestMemoryProfiler(t *testing.T) {
+	t.Skip("broken test - see issue 8867")
 	// Create temp file for the profile.
 	f, err := ioutil.TempFile("", "memprof")
 	if err != nil {