chore: Remove unused nightly test runs script and task (#3147)

Author: mattcreaser

configuration/instrumentation-tests.gradle

@@ -41,15 +41,6 @@ subprojects {
                     }
                 }
             }
-            task runNightlyTestsInDeviceFarmPool {
-                dependsOn(assembleAndroidTest)
-                doLast {
-                    exec {
-                        commandLine("$rootDir.path/scripts/run_nightly_tests_in_devicefarm_pool.sh")
-                        args([project.name])
-                    }
-                }
-            }
             task runCanaryInDeviceFarm {
                 dependsOn(assembleAndroidTest)
                 doLast {