Eliminate ICU's .dat lookup from bionic

Before this CL bionic did the following:

 * Finds the ICU .dat file with scandir()
 * Extracts the ICU version number from the file name. e.g. _63
 * dlopen() libicuuc
 * dlsym() necessary symbols, e.g. <symbol name>_<icu version>

Right now such ICU symbols are stored in libandroidicu.so and suffixed
with "_android", so it is responsible for "redirecting" to functions
with approriate version and we do not need to lookup the version on our
own. libicuuc is still available for NDK (and apps), and libandroidicu is
a subset of libicuuc and libicui18n.

After this CL bionic will do the following:

 * dlopen() libandroiicu
 * dlsym() <symbol_name>_android (without specific version suffix)

Bug: 122822987
Test: cts-tradefed run cts-dev -m CtsBionicTestCases
Change-Id: Iabd9f35b9c3462739fd2b18e60dcdc3e202031ac