RFR: 8211033: Clean up the processing -classpath argument not to set LM_CLASS

[Jaikiran Pai]

Can I please get a review of this change which addresses https://bugs.openjdk.org/browse/JDK-8211033?

As noted in that issue, this is a clean up of the code which determines the "mode" through with the `java` application is being launched. In its current form the presence of `--classpath` (or its equivalent arguments) was unnecessary updating the mode to `LM_CLASS`. The commit in this PR removes that part to allow for the mode to be detected based merely on the presence (or absence) of `-m`, `-jar`, `--source` options. If neither is specified, the file extension is checked to determine the launch mode. 

Given the nature of this clean up, no new tests have been introduced. Existing tests in tier1, tier2, tier3 continue to pass with this change.

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Commit messages:
 - 8211033: Clean up the processing -classpath argument not to set LM_CLASS

Changes: https://git.openjdk.org/jdk/pull/21971/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21971&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8211033
  Stats: 8 lines in 1 file changed: 3 ins; 5 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21971.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21971/head:pull/21971

PR: https://git.openjdk.org/jdk/pull/21971