Add more tests in NetworkCapabilitiesTest.java

Test deduceRestrictedCapability(), getAdministratorUids(),
setAdministratorUids(), getNetworkSpecifier(), getOwnerUid(),
setLinkDownstreamBandwidthKbps(), setLinkUpstreamBandwidthKbps(),
setSignalStrength() and Builder().

Bug: 139268426
Bug: 135998869
Bug: 138306002
Test: atest CtsNetTestCasesLatestSdk:android.net.NetworkCapabilitiesTest
Change-Id: I525941c47b71cd61ee872fd4d71b02a5d3767e21
Merged-In: I90c7a8c47710ea4ad8e8d2682c10440fd7f82270