Don't print warnings when testing utility functions

[cheister]

Don't print test output for regular build.

bazel build //...

DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming com.android.support:appcompat-v7:aar:28.0.0 should be interpreted as com.android.support:appcompat-v7:28.0.0@aar
DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming com.android.support:appcompat-v7:aar:28.0.0 should be interpreted as com.android.support:appcompat-v7:28.0.0@aar
DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming org.mockito:mockito-core:jar:3.3.3 should be interpreted as org.mockito:mockito-core:3.3.3@jar
DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming androidx.arch.core:core-testing:aar:2.1.0 should be interpreted as androidx.arch.core:core-testing:2.1.0@aar
DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming org.mockito:mockito-core:pom:3.3.3 should be interpreted as org.mockito:mockito-core:3.3.3@pom
DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming group:artifact:test-jar:1.2.3 should be interpreted as group:artifact:1.2.3@test-jar
DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming groupId:artifactId:bundle:1.2.3 should be interpreted as groupId:artifactId:1.2.3@bundle
DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming org.eclipse.aether:aether-api:jar:1.1.0 should be interpreted as org.eclipse.aether:aether-api:1.1.0@jar
DEBUG: rules_jvm_external/private/rules/v1_lock_file.bzl:123:18: Received different passwords for a@c1! Only using the first
DEBUG: rules_jvm_external/private/rules/v1_lock_file.bzl:116:22: Received multiple logins for machine 'c1'! Only using 'a'
DEBUG: rules_jvm_external/private/rules/v1_lock_file.bzl:123:18: Received different passwords for a@c1! Only using the first
DEBUG: rules_jvm_external/private/rules/v1_lock_file.bzl:116:22: Received multiple logins for machine 'c1'! Only using 'a'
DEBUG: rules_jvm_external/private/rules/v1_lock_file.bzl:116:22: Received multiple logins for machine 'c1'! Only using 'a1'
DEBUG: rules_jvm_external/private/rules/v1_lock_file.bzl:116:22: Received multiple logins for machine 'c1'! Only using 'a1'
DEBUG: rules_jvm_external/private/rules/v1_lock_file.bzl:116:22: Received multiple logins for machine 'c1'! Only using 'a1'
DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming groupId:artifactId:test-jar:1.2.3 should be interpreted as groupId:artifactId:1.2.3@test-jar
DEBUG: rules_jvm_external/private/lib/coordinates.bzl:85:18: Assuming groupId:artifactId:bundle:1.2.3 should be interpreted as groupId:artifactId:1.2.3@bundle