force dex2oat target executables to be compiled for 32-bit

64-bit dex2oat doesn't support 32-bit targets yet, force dex2oat
target executables to compile 32-bit for now by passing in a
value for LOCAL_MULTILIB to build-art-executable.

Bug: 13764385
Change-Id: I41adba1e64f373e4b61a3c13af2592ed4f7d0b57
Conflicts:
	build/Android.executable.mk
Recognize and ignore options '-ea' and '-da'

-ea:<package or class> and -da:<package or class> options are ignored.

This patch just adds -ea and -da options without any package or
class specified.

Change-Id: Ide04b8eacb1b2edb415328130bc12e05dc3ddc7b
Signed-off-by: Yevgeny Rouban <yevgeny.y.rouban@intel.com>