RFR: JDK-8278014: [vectorapi] Remove test run script

[Paul Sandoz]

Remove Vector API scripts for building and running tests. `jtreg` should be used instead.

Also updated the test generation script to remove options that assume mercurial as the code repository.

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Commit messages:
 - JDK-8278014: [vectorapi] Remove test run script

Changes: https://git.openjdk.java.net/jdk/pull/6621/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6621&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8278014
  Stats: 158 lines in 5 files changed: 0 ins; 156 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6621.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6621/head:pull/6621

PR: https://git.openjdk.java.net/jdk/pull/6621