Add a test to verify the dex_pc is correct.

The libunwindstack code will attempt to dlopen the libdexfile.so
when a dex pc is found. Unfortunately, this failed since that
library was not properly listed as a runtime library. To make
sure this doesn't happen again, add an end to end test that
will create a dex pc frame, and will verify the correct
dex function name is in that frame.

Bug: 199043576

Test: Unit test passes on arm/aarch64/x86/x86_64.
Test: Removed the runtime_libs of libdexfile from libunwindstack
Test: and verified the new test fails.
Change-Id: I3a11f9ee44e06e37a547d193b04f7fbb90ccfe0a