RFR: 8287400: Make BitMap range parameter names consistent

[Afshin Zafari]

The ranges are determined by 'start' and 'end' all over the bitMap.hpp and bitMap.cpp. All instances of other names for start and end are replaced.

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Commit messages:
 - 8287400: Make BitMap range parameter names consistent

Changes: https://git.openjdk.org/jdk/pull/11375/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11375&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8287400
  Stats: 129 lines in 2 files changed: 0 ins; 0 del; 129 mod
  Patch: https://git.openjdk.org/jdk/pull/11375.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11375/head:pull/11375

PR: https://git.openjdk.org/jdk/pull/11375