Adds regression test for bitfield naming bug

Author: hannes-steffenhagen-diffblue

regression/goto-instrument/bitfield_naming/main.c

@@ -0,0 +1,18 @@
+typedef struct {
+  unsigned char b11 : 1;
+  unsigned char b22 : 1;
+  unsigned char b34 : 2;
+  unsigned char b58 : 4;
+} bf_t;
+
+typedef union {
+  unsigned char val;
+  bf_t bf;
+} union_bf_t;
+
+int main(void)
+{
+  union_bf_t bf;
+  bf.bf.b11 = 1;
+  return 0;
+}

regression/goto-instrument/bitfield_naming/test.desc

@@ -0,0 +1,15 @@
+CORE
+main.c
+--show-goto-functions --json-ui
+^EXIT=0$
+^SIGNAL=0$
+BF1\{U8\}\$U8\$\'b11\'
+BF1\{U8\}\$U8\$\'b22\'
+BF2\{U8\}\$U8\$\'b34\'
+BF4\{U8\}\$U8\$\'b58\'
+--
+--
+
+Checks that type2name generates the right names for structs containing bitfields,
+in particular including the width of bitfield fields.
+