Refactor Examples to use assert_eq

This commit updates all example files to use `assert_eq!` for verifying
output, replacing the previous `Output:` comments. This change makes the
examples more robust and self-testing.

The benchmark results in some examples have also been slightly adjusted,
reflecting minor performance variations after the refactoring.

Additionally, a runtime panic handling mechanism has been introduced in
the VM for function calls, which improves error reporting for unexpected
panics.

examples/repeat.myc

@@ -1,3 +1,5 @@
+;; Benchmark: 18.8us
+;; Benchmark-Repeat: 113
 (do
   (repeat n 10 (print n)
 )