Move tests in the same directory as the corresponding code, so it's
easier to see what is/isn't tested.
Fix naming of libcutils_tests (plural) to match the singular that's more
common (even though the plural makes more sense to me).
Add these two to system/core/'s TEST_MAPPING.
Remove obsolete AndroidTest.xml.
Fix a flaky (timing-dependent) libcutils test.
Test: ran tests
Change-Id: I7e0a31ff45c8a152562bf66fc97161594249366e
Test accessing a singleton from two libraries, the second of which
depends on the first but is dlopen'd after the first is already
loaded.
Bug: 35674422
Test: out/host/linux-x86/nativetest64/libutils_tests/libutils_tests
Change-Id: I975ba933a19b941a52bdb6e9c221a6910ffb8081
