test: Fix VLA declarations

C++ doesn't support VLAs, but none of the uses were actually intended to
be dynamic. Instead, refactor out array lengths into constexpr
expressions.

Change-Id: I60dfd5c8552a249a7b28b663e7d4e5d1fdfa96e0
Signed-off-by: William A. Kennington III <wak@google.com>
2 files changed