Add a function that fails softly if libdexfile(d)_external.so cannot be
loaded.

libunwindstack needs it since it is used in situations where we cannot
guarantee that libdexfile_external.so is available, e.g. from
libc_malloc_debug.so in the bootstrap Bionic.

Test: m test-art-host-gtest-art_libdexfile_support_tests
Test: m test-art-host-gtest-art_libdexfile_support_static_tests
Bug: 139408016
Change-Id: I0c311222baaafbf5c3a0f7d3f9f2d83d4abbaf90
2 files changed