Fix nullity check for ObjectReference

21 jobs from fix-is_null in 2 minutes and 35 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Build
failed #20489
build

02:35

 
  Test
skipped #20490
test:cargo:api
skipped #20492
test:cargo:compiler
skipped #20491
test:cargo:ir
skipped #20493
test:cargo:runtime
skipped #20499
testjit:binops
skipped #20500
testjit:cmpops
skipped #20501
testjit:controlflow
skipped #20502
testjit:convops
skipped #20503
testjit:double
skipped #20504
testjit:memops
skipped #20498
testjit:milestones
skipped #20505
testjit:otherops
skipped #20506
testjit:rpython
skipped #20507
testjit:som
skipped #20497
testmuc:test_binop
skipped #20496
testmuc:test_cmp
skipped #20494
testmuc:test_simple
skipped #20495
testmuc:test_swapstack
 
  Mubench
skipped #20508
mubench
 
  Rustfmt
skipped #20509
rustfmt