RFR: [bworld] BasicAccessFlags and JavaBaseCheckSince failing

[Chen Liang]

NULL_CHECKED with mask 0x200 should be ranked near INTERFACE which also has 0x200. Checks need to use `@since Valhalla` instead of `valhalla` to inform `JavaBaseCheckSince`. These are the test failures I see from running tier 1 and 2 on Oracle's CI.

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Commit messages:
 - [bworld] BasicAccessFlags and JavaBaseCheckSince failing

Changes: https://git.openjdk.org/valhalla/pull/2042/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=2042&range=00
  Stats: 25 lines in 2 files changed: 12 ins; 12 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/2042.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2042/head:pull/2042

PR: https://git.openjdk.org/valhalla/pull/2042