[8u] RFR + RFA 8211926: Catastrophic size_t underflow in BitMap::*_large methods

[Aleksey Shipilev]

Please review and approve the backport of catastrophic underflow fix in BitMap:

  Original Bug:
      URL: https://bugs.openjdk.java.net/browse/JDK-8211926
      Reporter: Aleksey Shipilev
      Assignee: Aleksey Shipilev
      Priority: P4
      Components: hotspot

  Original Fix:
        12: JDK-8211926, http://hg.openjdk.java.net/jdk/jdk/rev/e5534cc91a10, 88 day(s) ago

  Backports and Forwardports:
        11: 11.0.3, JDK-8214860, http://hg.openjdk.java.net/jdk-updates/jdk11u/rev/6c90d1d1a03b, 63
day(s) ago
         8: MISSING

8u fix does not apply cleanly, because Bitmap is cleaned up a bit in subsequent releases. There is
also no support for gtest, which means we cannot backport the relevant regression test. Instead, we
have to rely on assert to fire if code is broken. 8u webrev:
  http://cr.openjdk.java.net/~shade/8211926/webrev.8u.01/

Testing: Linux x86_64 build and all jtreg tests (with some unrelated failures)

Thanks,
-Aleksey