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/macro_unless.myc

@@ -1,9 +1,8 @@
-;; Benchmark: 55ns
-;; Benchmark-Repeat: 36062
+;; Benchmark: 108ns
+;; Benchmark-Repeat: 18646
 ;; Classic "unless" macro example
 ;; Demonstrates simple template substitution.
-;; Output: 42
 
 (do
     (macro unless [c b] `(if ~c ... ~b))
-    (unless false 42))
+    (assert-eq 42 (unless false 42)))