RFR: 8171508: Remove -Dsun.java.launcher.is_altjvm option [v3]

[Calvin Cheung]

> This change fixes two issues in `os::jvm_path()`:
> 
> - go back 4 instead of 5 slashes and then checking for "/jre/lib";
> - fix the hardcoded "hotspot" sub-directory before the jvm library name.
> 
> Passed tiers 1 - 3 testing.

Calvin Cheung has updated the pull request incrementally with one additional commit since the last revision:

  @dholmes-ora comment

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Changes:
  - all: https://git.openjdk.org/jdk/pull/24310/files
  - new: https://git.openjdk.org/jdk/pull/24310/files/eb20233a..33a7ad26

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24310&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24310&range=01-02

  Stats: 18 lines in 4 files changed: 0 ins; 4 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/24310.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24310/head:pull/24310

PR: https://git.openjdk.org/jdk/pull/24310