Update bookrunner expectation after rust-lang#1061 fix (rust-lang#1077)

Author: celinval

scripts/ci/detect_bookrunner_failures.sh

@@ -10,7 +10,7 @@ set -eu
 # The threshold is roughly computed as: `1.05 * <number of expected failures>`
 # The extra 5% allows us to account for occasional timeouts. It is reviewed and
 # updated whenever the Rust toolchain version is updated.
-EXPECTED=94
+EXPECTED=82
 THRESHOLD=$(expr ${EXPECTED} \* 105 / 100) # Add 5% threshold
 
 if [[ $# -ne 1 ]]; then
@@ -29,6 +29,8 @@ NUM_FAILURES=${strarr[-1]}
 # Print a message and return a nonzero code if the threshold is exceeded
 if [[ $NUM_FAILURES -ge $THRESHOLD ]]; then
     echo "Error: The number of failures from bookrunner is higher than expected!"
+    echo
+    echo "Found $NUM_FAILURES which is higher than the threshold of $THRESHOLD"
     echo "This means that your changes are causing at least 5% more failures than in previous bookrunner runs."
     echo "To check these failures locally, run \`cargo run -p bookrunner\` and inspect the report in \`build/output/latest/html/index.html\`."
     echo "For more details on bookrunner, go to https://model-checking.github.io/kani/bookrunner.html"