Move SpannedTestUtils into tests

SpannedTestUtils was only used by test code but was built as
part of the production code. This change moves it into the tests
subdirectory to prevent that from happening.

Bug: 30188076
Test: make checkbuild after removing junit from API
Change-Id: I38dade765fa81046eb4cc19240d6faf1a7203b15
diff --git a/src/com/android/contacts/common/format/SpannedTestUtils.java b/tests/src/com/android/contacts/common/format/SpannedTestUtils.java
similarity index 100%
rename from src/com/android/contacts/common/format/SpannedTestUtils.java
rename to tests/src/com/android/contacts/common/format/SpannedTestUtils.java