libbinder_ndk: core object type comparison

Comparison operators for core types which are missing these, in order to
support comparison of arbitrary NDK backend types.

Bug: 175018841
Test: atest CtsNdkBinderTestCases
Change-Id: I3c112d0883c4d51fd5376709f3db4d72b6883697
Merged-In: I3c112d0883c4d51fd5376709f3db4d72b6883697