Add heap reference size to the checks in arch_test

As we will potentially make heap references larger than 32b on 64b
systems at some point, add a constant to the .h files that describes
what the current assembly implementation assumes about the size of
heap references, and check whether that agrees with sizeof.

Change-Id: I75ffd7e2b59891ec36977fd831a8d5faac69c76d

Conflicts:
	runtime/arch/arch_test.cc
	runtime/arch/arm64/asm_support_arm64.h
	runtime/arch/x86_64/asm_support_x86_64.h
ART: Fix target run-tests to build architecture directories

The recent dalvik-cache layout changes require the tests to create
the right directories, as ART does not auto-create outside of /tmp

(cherry picked from commit 335438a512d016bb0e582304c0a6a1ad510bcc47)

Change-Id: Ie9045cc34be8b2f106fdec4f3bf37ad830637756

Conflicts:
	test/etc/push-and-run-test-jar