When debugging, I noticed that ConstantOopReadValue::print_on prints 'nullptr' instead of 'NULL' for a field value:

ScopeDesc(pc=0x00002e13849f2a10 offset=970):
   Test::racyStringConstructionCodepointsSurrogates@110 (line 60) reexecute=true
   Locals
    - l0: empty
    - l1: empty
    - l2: empty
    - l3: stack[24],oop
    - l4: empty
    - l5: merge_obj[708]
    - l6: empty
   Expression stack
    - @0: reg rbp [10],int
    - @1: 1000000
   Objects
    - 0: R merge_obj[708], selector="stack[8]", candidate_objs=[709, 710]
    - 1: obj[709], java.lang.String
        Fields: 0, 0, 0, stack[40],oop
    - 2: obj[710], java.lang.String
        Fields: 0, 0, 0, nullptr

This is a regression from JDK-8300242. We should also check related code.