Make xla_cc_test default to static linking, so that we can catch bugs where duplicated symbols are linked into the same test (e.g. having main()s from different libraries), which is unintended and leads to wrong/surprising test behavior, as we don't know for sure which main() the linker will use.

Make xla_cc_test default to static linking, so that we can catch bugs where duplicated symbols are linked into the same test (e.g. having main()s from different libraries), which is unintended and leads to wrong/surprising test behavior, as we don't know for sure which main() the linker will use. #3792