DnsResolver: make libcrypto a shared lib.

A statically linked libcrypto's self test will not succeed because
the linker step (symbol relocations etc.) will change the checksum.

Since libssl is also provided by boringssl, we're giving it the
same treatment for consistency.

Note that the DnsResolver module carries its own copies of these
shared libraries on-device:

$ adb shell 'su 0 find /apex/com.android.resolv/ -name "*.so"'
/apex/com.android.resolv/lib64/libnetd_resolv.so
/apex/com.android.resolv/lib64/libcrypto.so
/apex/com.android.resolv/lib64/libssl.so

Bug: 137267623
Test: Treehugger

Change-Id: Ia418f379b7a8c8ede6539ce735a19c7f284bbce7