teamcity: don't sign binaries on CI

.teamcity/settings.kts

@@ -258,6 +258,7 @@ class TestBuild(val os: String, val arch: String, val version: String, buildId:
                     name = "Test"
                     path = "_scripts/test_mac.sh"
                     arguments = "${"go$version"} $arch %system.teamcity.build.tempDir%"
+                    param("env.CI", "true")
                 }
             }
         }

_scripts/make.go

@@ -130,6 +130,9 @@ This option can only be specified if testset is basic or a single package.`)
 }
 
 func checkCert() bool {
+	if os.Getenv("CI") != "" {
+		return true
+	}
 	if os.Getenv("NOCERT") != "" {
 		return false
 	}