Deduplicate fuzz cases on the frontend before they are displayed.

fuzzer/go/frontend/data/stacktrace.go

 package data
 
 import (
         "bufio"
         "bytes"
         "fmt"
         "regexp"
         "strconv"
         "strings"
 
@@ skipping 136 matching lines @@
                         hasBegun = true
                         continue
                 }
                 if hasBegun && line == "" {
                         break
                 }
                 if !hasBegun {
                         continue
                 }
 
+                line = strings.Replace(line, "(anonymous namespace)::", "", -1)
+
                 if match := asanStackTraceLine.FindStringSubmatch(line); match != nil {
                         // match[0] is the entire matched portion, [1] is the function name [2] is the
                         // "package", [3] is the file name, [4] is the line number
                         newFrame := FullStackFrame(match[2], match[3], match[1], safeParseInt(match[4]))
                         frames = append(frames, newFrame)
                 }
         }
         return StackTrace{Frames: frames}
 }
 
@@ skipping 15 matching lines @@
         s := fmt.Sprintf("StackTrace with %d frames:\n", len(st.Frames))
         for _, f := range st.Frames {
                 s += fmt.Sprintf("\t%s\n", f.String())
         }
         return s
 }
 
 func (st *StackTrace) IsEmpty() bool {
         return len(st.Frames) == 0
 }