Fix search for implicit null check.

There are additional instructions that can be emitted at use
site for x86/x86-64, such as ArrayLength, and the implicit
null check may therefore be emitted later than at the next
instruction. Search for the implicit null check until we
reach an instruction that's not emitted at use site.

This also reverts the blacklisting of the test, i.e.
    commit 5be5260cfec2fc0a8c21ef1a08e7144523a8bfcd.

Test: testrunner.py --host \
      --jit-on-first-use --debuggable -t 122-npe
Test: testrunner.py --host \
      --optimizing --jit --jit-on-first-use \
      --debuggable --ndebuggable
Bug: 136021898
Change-Id: I768f55d8c8975dbd0376802c10ca8508df3fe3b0

0 files changed, 0 insertions, 0 deletions