cmd/link: test that findfunctab is in gopclntab section

This is a test for CL 719743.

Change-Id: I2d7b9d00d2d4dd63a21ca00f09eb7c9378ec70f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/721461
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>

src/cmd/link/link_test.go

@@ -2109,4 +2109,8 @@ func TestFuncdataPlacement(t *testing.T) {
 			}
 		}
 	}
+
+	if uint64(moddata.findfunctab)-imageBase < pclntabAddr || uint64(moddata.findfunctab)-imageBase >= pclntabEnd {
+		t.Errorf("findfunctab address %#x not between %#x and %#x", moddata.findfunctab, pclntabAddr, pclntabEnd)
+	}
 }