libclat_test: use static libc++

shot in the dark fix for mainline T test failure:

libclat_test did not report any run:
CANNOT LINK EXECUTABLE "/data/local/tmp/libclat_test": cannot locate symbol "_ZTVNSt3__118basic_stringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE" referenced by "/data/local/tmp/libclat_test"...

Bug: 398136085
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I10fea4441898a19430941ef4aa1951817cc350ba
1 file changed