RFR: 8296620: Removed total_space_rs from MetaspaceShared::map_archives()

[Ioi Lam]

The `total_space_rs` variable is passed around by several functions in the `MetaspaceShared` class. However, it's used only inside `MetaspaceShared::reserve_address_space_for_archives()`.

We should remove it from other functions and simplify the interfaces.

-------------

Commit messages:
 - 8296620: Removed total_space_rs from MetaspaceShared::map_archives()

Changes: https://git.openjdk.org/jdk/pull/11050/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11050&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8296620
  Stats: 28 lines in 2 files changed: 1 ins; 15 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/11050.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11050/head:pull/11050

PR: https://git.openjdk.org/jdk/pull/11050