runtime: disable pageAlloc tests on OpenBSD in short mode

This change disables pageAlloc tests on OpenBSD in short mode because
pageAlloc holds relatively large virtual memory reservations and we make
two during the pageAlloc tests. The runtime may also be carrying one
such reservation making the virtual memory requirement for testing the
Go runtime three times as much as just running a Go binary.

This causes problems for folks who just want to build and test Go
(all.bash) on OpenBSD but either don't have machines with at least 4ish
GiB of RAM (per-process virtual memory limits are capped at some
constant factor times the amount of physical memory) or their
per-process virtual memory limits are low for other reasons.

Fixes #36210.

Change-Id: I8d89cfde448d4cd2fefff4ad6ffed90de63dd527
Reviewed-on: https://go-review.googlesource.com/c/go/+/212177
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

src/runtime/mgcscavenge_test.go

@@ -272,6 +272,9 @@ func TestPallocDataFindScavengeCandidate(t *testing.T) {
 
 // Tests end-to-end scavenging on a pageAlloc.
 func TestPageAllocScavenge(t *testing.T) {
+	if GOOS == "openbsd" && testing.Short() {
+		t.Skip("skipping because virtual memory is limited; see #36210")
+	}
 	type test struct {
 		request, expect uintptr
 	}

src/runtime/mpagealloc_test.go

@@ -41,6 +41,9 @@ func checkPageAlloc(t *testing.T, want, got *PageAlloc) {
 }
 
 func TestPageAllocGrow(t *testing.T) {
+	if GOOS == "openbsd" && testing.Short() {
+		t.Skip("skipping because virtual memory is limited; see #36210")
+	}
 	type test struct {
 		chunks []ChunkIdx
 		inUse  []AddrRange
@@ -216,6 +219,9 @@ func TestPageAllocGrow(t *testing.T) {
 }
 
 func TestPageAllocAlloc(t *testing.T) {
+	if GOOS == "openbsd" && testing.Short() {
+		t.Skip("skipping because virtual memory is limited; see #36210")
+	}
 	type hit struct {
 		npages, base, scav uintptr
 	}
@@ -589,6 +595,9 @@ func TestPageAllocAlloc(t *testing.T) {
 }
 
 func TestPageAllocExhaust(t *testing.T) {
+	if GOOS == "openbsd" && testing.Short() {
+		t.Skip("skipping because virtual memory is limited; see #36210")
+	}
 	for _, npages := range []uintptr{1, 2, 3, 4, 5, 8, 16, 64, 1024, 1025, 2048, 2049} {
 		npages := npages
 		t.Run(fmt.Sprintf("%d", npages), func(t *testing.T) {
@@ -638,6 +647,9 @@ func TestPageAllocExhaust(t *testing.T) {
 }
 
 func TestPageAllocFree(t *testing.T) {
+	if GOOS == "openbsd" && testing.Short() {
+		t.Skip("skipping because virtual memory is limited; see #36210")
+	}
 	tests := map[string]struct {
 		before map[ChunkIdx][]BitRange
 		after  map[ChunkIdx][]BitRange
@@ -867,6 +879,9 @@ func TestPageAllocFree(t *testing.T) {
 }
 
 func TestPageAllocAllocAndFree(t *testing.T) {
+	if GOOS == "openbsd" && testing.Short() {
+		t.Skip("skipping because virtual memory is limited; see #36210")
+	}
 	type hit struct {
 		alloc  bool
 		npages uintptr

src/runtime/mpagecache_test.go

@@ -180,6 +180,9 @@ func TestPageCacheAlloc(t *testing.T) {
 }
 
 func TestPageCacheFlush(t *testing.T) {
+	if GOOS == "openbsd" && testing.Short() {
+		t.Skip("skipping because virtual memory is limited; see #36210")
+	}
 	bits64ToBitRanges := func(bits uint64, base uint) []BitRange {
 		var ranges []BitRange
 		start, size := uint(0), uint(0)
@@ -254,6 +257,9 @@ func TestPageCacheFlush(t *testing.T) {
 }
 
 func TestPageAllocAllocToCache(t *testing.T) {
+	if GOOS == "openbsd" && testing.Short() {
+		t.Skip("skipping because virtual memory is limited; see #36210")
+	}
 	tests := map[string]struct {
 		before map[ChunkIdx][]BitRange
 		scav   map[ChunkIdx][]BitRange