Adding const variables tests

The tests relating to structs and unions are marked as known bugs as
they are related to diffblue#355

Author: thk123

regression/goto-instrument-typedef/typedef-const-struct1/main.c

@@ -0,0 +1,12 @@
+
+typedef struct tag_struct_name
+{
+  int x;
+  float y;
+} MYSTRUCT;
+
+void fun()
+{
+  const struct tag_struct_name tag_struct_var = {.x = 1, .y = 3.14f};
+  const MYSTRUCT mystruct_var = {.x = 3, .y = 2.1f};
+}

regression/goto-instrument-typedef/typedef-const-struct1/test.desc

@@ -0,0 +1,11 @@
+KNOWNBUG
+main.c
+"--show-symbol-table"
+// Enable multi-line checking
+-Pzo
+EXIT=0
+SIGNAL=0
+(?s)Base name\.+: tag_struct_var.Mode\.+: C.Type\.+: const struct tag_struct_name
+(?s)Base name\.+: mystruct_var.Mode\.+: C.Type\.+: const MYSTRUCT
+--
+warning: ignoring

regression/goto-instrument-typedef/typedef-const-type1/main.c

@@ -0,0 +1,8 @@
+
+typedef int MYINT;
+
+void fun()
+{
+  const int int_var = 3;
+  const MYINT myint_var = 5;
+}

regression/goto-instrument-typedef/typedef-const-type1/test.desc

@@ -0,0 +1,11 @@
+CORE
+main.c
+"--show-symbol-table"
+// Enable multi-line checking
+-Pzo
+EXIT=0
+SIGNAL=0
+(?s)Base name\.+: int_var.Mode\.+: C.Type\.+: const signed int
+(?s)Base name\.+: myint_var.Mode\.+: C.Type\.+: const MYINT
+--
+warning: ignoring

regression/goto-instrument-typedef/typedef-const-union1/main.c

@@ -0,0 +1,12 @@
+
+typedef union tag_union_name
+{
+  int x;
+  float y;
+} MYUNION;
+
+void fun()
+{
+  const union tag_union_name tag_union_var = {1};
+  const MYUNION myunion_var = {.y = 2.1f};
+}

regression/goto-instrument-typedef/typedef-const-union1/test.desc

@@ -0,0 +1,11 @@
+KNOWNBUG
+main.c
+"--show-symbol-table"
+// Enable multi-line checking
+-Pzo
+EXIT=0
+SIGNAL=0
+(?s)Base name\.+: tag_union_var.Mode\.+: C.Type\.+: const union tag_union_name
+(?s)Base name\.+: myunion_var.Mode\.+: C.Type\.+: const MYUNION
+--
+warning: ignoring