Fix: Move InterpreterCache to right below tlsPtr_

Don't undefine ALIGN_UP at the end of the file.

THREAD_INTERPRETER_CACHE_OFFSET is defined in terms of ALIGN_UP,
if ALIGN_UP is undefined, the code does not compile.

Note that I intend to remove this whole file very soon anyway.

Test: THREAD_INTERPRETER_CACHE_OFFSET can be used from assembly
Change-Id: If126c350a8010eec1877b241c5220a63637c1ebd