Refine module name resolving in multilib build

-- Added TARGET_PREFER_32_BIT, which sets LOCAL_32_BIT_ONLY for an
   executable, if LOCAL_NO_2ND_ARCH is not true.

Name resolving in 64-bit multilib build:
-- Name resolving in PRODUCT_PACKAGES:
   foo:32 resolves to foo_32;
   foo:64 resolves to foo;
   foo resolves to both foo and foo_32 (if foo_32 is defined).

-- Name resolving for LOCAL_REQUIRED_MODULES:
   If a module is built for 2nd arch, its required module resolves to
   32-bit variant, if it exits;
   Otherwise for executable and shared library, a required module
   resolves to the default 64-bit variant; for other module classes,
   required module foo resolves to both foo and foo_32 (if foo_32 is
   defined)

Bug: 12898862
Change-Id: I5fda1a77f58814097b10b5ad2743ee25adfaecc4