Fix stack overflow in PhoneNumberUtilsTest

Leave space for adding the trailing null in the buffer used to call
phone_number_stripped_reversed_inter, and add an assertion to prevent
writing outside the buffer.

Test: USE_HOST_MUSL=true atest --host --no-bazel libsqlite3_phone_number_utils_test
Change-Id: Idbca51b38a7104536f9675c623f8e221663f6455
1 file changed