internal/lsp/regtest: standardize on 20s timeout

The default regtest timeout was increased to 60s a while ago to try to
avoid flakes.

We think we've figured out the flakes, so drop it back down.  Start with
20s, since TestGOMODCACHE (which had overridden its timeout to 5s)
occasionally fails on freebsd:
https://build.golang.org/log/6c607c7fd3e886cf23127c958ae17637440fbc63

Change-Id: I10e6927985b8fb1d149070e204bd8ca120309c7b
Reviewed-on: https://go-review.googlesource.com/c/tools/+/240060
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
diff --git a/internal/lsp/regtest/reg_test.go b/internal/lsp/regtest/reg_test.go
index 0837fae..ab4602a 100644
--- a/internal/lsp/regtest/reg_test.go
+++ b/internal/lsp/regtest/reg_test.go
@@ -20,7 +20,7 @@
 var (
 	runSubprocessTests       = flag.Bool("enable_gopls_subprocess_tests", false, "run regtests against a gopls subprocess")
 	goplsBinaryPath          = flag.String("gopls_test_binary", "", "path to the gopls binary for use as a remote, for use with the -enable_gopls_subprocess_tests flag")
-	regtestTimeout           = flag.Duration("regtest_timeout", 60*time.Second, "default timeout for each regtest")
+	regtestTimeout           = flag.Duration("regtest_timeout", 20*time.Second, "default timeout for each regtest")
 	skipCleanup              = flag.Bool("regtest_skip_cleanup", false, "whether to skip cleaning up temp directories")
 	printGoroutinesOnFailure = flag.Bool("regtest_print_goroutines", false, "whether to print goroutines info on failure")
 )