Add a test for the same-named static functions crashing dependence graph in the goto-analyser

Author: NlightNFotis

regression/goto-analyzer/dependence-graph6/file1.c

@@ -0,0 +1,11 @@
+extern int s1;
+static void sub(void)
+{
+  if (s1) {
+  }
+}
+
+void f1(void)
+{
+  sub();
+}

regression/goto-analyzer/dependence-graph6/file2.c

@@ -0,0 +1,11 @@
+extern int s2;
+static void sub(void)
+{
+  if (s2) {
+  }
+}
+
+void f2(void)
+{
+  sub();
+}

regression/goto-analyzer/dependence-graph6/main.c

@@ -0,0 +1,8 @@
+void f1(void);
+void f2(void);
+
+void main(void)
+{
+  f1();
+  f2();
+}

regression/goto-analyzer/dependence-graph6/test.desc

@@ -0,0 +1,9 @@
+CORE
+main.c
+file1.c file2.c --dependence-graph --show
+^EXIT=0$
+^SIGNAL=0$
+--
+Assertion .+ failed
+--
+