Can we dump more pretty CFG file format for C1 compiler HIR

[kelthuzadx]

`+XX:+PrintCFGToFile` could dump ssa-based HIR into file, but its format is messy:```cfg
    begin_states
      begin_locals
        size 3
        method "static jint com.github.kelthuzadx.HelloWorld.jerkSum(jint)"
 1  i7 "[R570|I]" 
      end_locals
    end_states
    begin_HIR
.22 0 i15 ireturn i7 <|@
    end_HIR
    begin_LIR
  42 label [label:0x000002136a396400] <|@ 
  44 move [R570|I] [rax|I]  <|@ 
  46 return [rax|I]   <|@ 
    end_LIR
  end_block
end_cfg
begin_intervals
  name "Before Register Allocation"
3 fixed "[rax|I]" 3 570 [0, 1[ [44, 46[  "no spill store"
4 fixed "[rdx|I]" 4 -1 [0, 4[  "no definition"
569 int 569 4 [4, 10[ 4 M 10 S  "no spill store"
570 int 570 569 [10, 26[ [38, 44[ 10 M 26 S 38 M 41 L 44 S  "no optimization"
571 int 571 573 [12, 30[ [36, 42[ 12 M 18 M 28 S 30 S 36 M 41 L  "no optimization"
572 int 572 570 [26, 38[ 26 M 28 M 38 S  "no spill store"
573 int 573 571 [30, 36[ 30 M 32 M 36 S  "no spill store"
end_intervals


```
So can we produce more readable format?