go/pointer: skip TestInput on 32-bit platforms

This test was already memory-hungry to begin with, and apparently the
switch to go/packages in CL 356513 pushed it over the edge of the
32-bit address space (at least with the default GOGC setting). Rather
than trying to precisely tune it to skim under the 32-bit limit,
let's just skip the test on platforms with insufficient address space.

Updates golang/go#14113
Updates golang/go#48547

Change-Id: Iab99e9ce70a98034194d7c7ad7df7a545ac95ef3
Reviewed-on: https://go-review.googlesource.com/c/tools/+/360837
Trust: Bryan C. Mills <[email protected]>
Run-TryBot: Bryan C. Mills <[email protected]>
gopls-CI: kokoro <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Russ Cox <[email protected]>

Author: Bryan C. Mills

go/pointer/pointer_test.go

@@ -26,6 +26,7 @@ import (
 	"strconv"
 	"strings"
 	"testing"
+	"unsafe"
 
 	"golang.org/x/tools/go/callgraph"
 	"golang.org/x/tools/go/packages"
@@ -553,6 +554,9 @@ func TestInput(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping in short mode; this test requires tons of memory; https://golang.org/issue/14113")
 	}
+	if unsafe.Sizeof(unsafe.Pointer(nil)) <= 4 {
+		t.Skip("skipping memory-intensive test on platform with small address space; https://golang.org/issue/14113")
+	}
 	ok := true
 
 	wd, err := os.Getwd()