fix: make style checks fail if either test fails

Since `devtool` does not have `-e`, commands fail but don't fail the
test run.

Fixes:
dfb45dc

Signed-off-by: Pablo Barbáchano <[email protected]>

Author: pb8o

tools/devtool

@@ -935,8 +935,8 @@ cmd_mkdocs() {
 }
 
 cmd_checkstyle() {
-    cmd_test --no-build --no-kvm-check -- -n 4 --dist worksteal integration_tests/style
-    cmd_test --no-build --no-kvm-check -- -n 4 --doctest-modules framework
+    cmd_test --no-build --no-kvm-check -- -n 4 --dist worksteal integration_tests/style || exit 1
+    cmd_test --no-build --no-kvm-check -- -n 4 --doctest-modules framework || exit 1
 }
 
 # Check if able to run firecracker.