ANDROID: test_stackinit: work around LLVM PR44916

Temporarily move the local outside of switch statement to work around
https://bugs.llvm.org/show_bug.cgi?id=44916 and unbreak the
ClangBuiltLinux project Travis build.

This patch has been tested according to the instructions at
https://github.com/ClangBuiltLinux/continuous-integration



Bug: 149581678
Test: ./driver.sh REPO=android-4.14
Change-Id: Iea85ee09d8f0e6d698b5f23a02fe23a6002ad5e7
Signed-off-by: Alexander Potapenko <glider@google.com>