Add regression test demonstrating a function pointer restriction bug

Author: danpoe

regression/goto-instrument/restrict-function-pointer-goto-target/test.c

@@ -0,0 +1,16 @@
+#include <assert.h>
+
+typedef void (*fp_t)();
+
+void f()
+{
+}
+
+int main(void)
+{
+  fp_t fp = f;
+  goto L;
+
+L:
+  fp();
+}

regression/goto-instrument/restrict-function-pointer-goto-target/test.desc

@@ -0,0 +1,13 @@
+KNOWNBUG
+test.c
+--restrict-function-pointer main.function_pointer_call.1/f
+^EXIT=0$
+^SIGNAL=0$
+\[main.assertion.1\] line \d+ dereferenced function pointer at main.function_pointer_call.1 must be f: SUCCESS
+--
+--
+This test checks that a function pointer call that is the target of a goto (in
+the goto program) is correctly handled. Currently there is a bug, as the
+function pointer labelling step which is part of the restrict function pointer
+feature inserts a new instructions before the function pointer calls, but does
+not adjust the goto targets.