test/stdlib: Account for bugs in the builtin stdlib implementation
test/stdlib: Account for bugs in the builtin stdlib implementation

The strstr and strtoull implementations in EC's builtin C standard
library have some bugs. For now, create separate asserts depending on
whether we're using the builtin standard library or the one from the
toolchain.

BRANCH=none
BUG=b:234181908, b:243192369
TEST=make USE_BUILTIN_STDLIB=0 run-stdlib -j
TEST=make run-stdlib -j

Signed-off-by: Tom Hughes <fc5c12f30a5ed2baa0581f44ee14ad1eb7b20d83@chromium.org>
Change-Id: Ibcf7655c94373c63464bb3812afb5d37115f8880
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3843215
Reviewed-by: Andrea Grandi <f017805e76e0e7a74072a3bac1b6e29e65eedeab@google.com>
Reviewed-by: Bobby Casey <a3c107f0b4efaee07148ab0813ba992bba562a69@google.com>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec