go/packages: fix handling of NeedExportFile in go list

If we need the export file, can't use -find,
which stops the go command too early.

Change-Id: I82adca728e3e8a2435cddad14cfed97665ea4234
Reviewed-on: https://go-review.googlesource.com/c/tools/+/310510
Trust: Russ Cox <[email protected]>
Run-TryBot: Russ Cox <[email protected]>
Reviewed-by: Austin Clements <[email protected]>
Auto-Submit: Russ Cox <[email protected]>
gopls-CI: kokoro <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: rsc

go/packages/golist.go

@@ -819,7 +819,7 @@ func golistargs(cfg *Config, words []string) []string {
 		fmt.Sprintf("-deps=%t", cfg.Mode&NeedImports != 0),
 		// go list doesn't let you pass -test and -find together,
 		// probably because you'd just get the TestMain.
-		fmt.Sprintf("-find=%t", !cfg.Tests && cfg.Mode&findFlags == 0),
+		fmt.Sprintf("-find=%t", !cfg.Tests && cfg.Mode&findFlags == 0 && !usesExportData(cfg)),
 	}
 	fullargs = append(fullargs, cfg.BuildFlags...)
 	fullargs = append(fullargs, "--")