java_sdk_library: Remove some almost single use constants

The constants are only used in one place in the code and in the test.
This change switches the test code to use the apiScope methods to
generate the names and then inlines the constants in those methods. It
makes it easier to see the naming convention.

Test: m nothing
Bug: 155480189
Change-Id: I966e82b8ae67624da168e05f5a2b062b832cb8cd