linker: add more directories to default lib paths

Due to b/33681361, libraries are now installed to different paths than
before. In order for linker to load libraries from the new paths, the
default lib paths are updated.

However, this patch is temporary; different paths must be used depending
on whether the process is executing vendor executable or framework
executable. For example, vendor executable should not be able to access
/system/lib/, which is for framework-internal libs. Similarly,
framework executables should not be able to access /vendor/lib.

We have several solutions (linker namespace and DT_RUNPATH) to support
the scenario, but haven't concluded which is better. Furthermore, if we
restrict the search path right now, it will break many parts of Android
that are not yet prepared for the restriction. So, until then, we
temporarily use the single search path for both framework/vendor
executables.

Test: build & run
Change-Id: I806e9b4379bce96653b1dd3354b9f4801abb0411