Add system server pm to trigger CTS PackageManager tests

When the developers change any code in
frameworks/base/service/core/java/com/android/server/pm and
frameworks/base/service/core/java/android/content/pm, it should
invoke all of the tests under cts/hostsidetests/packagemanager.

service/core/java/com/android/server/pm/TEST_MAPPING already imports
core/java/android/content/pm/TEST_MAPPING which imports
cts/hostsidetests/packagemanager/TEST_MAPPING.

Test: atest --collect-test-only -p \
      cts/hostsidetests/packagemanager
Test: atest --collect-test-only -p \
      frameworks/base/services/core/java/com/android/server/pm
Test: atest --collect-test-only -p \
      frameworks/base/services/core/java/android/content/pm

Bug: 180650365
Change-Id: I8f2d971f46a4047cabaa5b3a7094e6033bbd66e9