Retracing test simple goto

This adds one test file for the new --retrace feature.

Author: lks9

regression/book-examples/simple-goto/C00.desc

@@ -0,0 +1,6 @@
+CORE
+simple_goto.c
+--function foo --retrace 00
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$

regression/book-examples/simple-goto/C01.desc

@@ -0,0 +1,6 @@
+CORE
+simple_goto.c
+--function foo --retrace 01
+^EXIT=10$
+^SIGNAL=0$
+^VERIFICATION FAILED$

regression/book-examples/simple-goto/C10.desc

@@ -0,0 +1,6 @@
+CORE
+simple_goto.c
+--function foo --retrace 10
+^EXIT=10$
+^SIGNAL=0$
+^VERIFICATION FAILED$

regression/book-examples/simple-goto/simple_goto.c

@@ -0,0 +1,15 @@
+#include <stdbool.h>
+#include <assert.h>
+
+void foo (bool arg1, bool arg2) {
+    bool v1 = false;
+    bool v2 = false;
+    if (arg1) goto l1;
+    v1 = true;
+l1:
+    if (arg2) goto l2;
+    v2 = true;
+l2:
+    assert (v1);
+    assert (v2);
+}