ndk-build: Do not copy prebuilt static libraries.

This patch modifies ndk-build to avoid copying prebuilt
static libraries un-necessarily. This fixes
http://code.google.com/p/android/issues/detail?id=40302

+ Add relevant unit test.

+ Make run-tests.sh copy tests with a 'build.sh' script
  to a temporary location, just like other ones.

Change-Id: Id474cd86880efade1d9f49125724f7708b03d07a
15 files changed