Support TARGET_TRANSLATE_2ND_ARCH case

Build-only change to support the multilib case where the second arch
is translated (and thus bluetooth library is needed).

"True" multilib case is explicitly not supported.

Test: Build system refactoring CL. Existing unit tests still pass.

BUG=31422117

Change-Id: I09f239d39f5dbe0848a89367327db1ea1074ca39