RFR: 8267805: Add UseVtableBasedCHA to the list of JVM flags known to jtreg

[Vladimir Ivanov]

A trivial change to enable `vm.opt.final.UseVtableBasedCHA` usage in `@requires`. 

It was omitted in #3727 and `compiler/cha/StrengthReduceInterfaceCall` hasn't been executed since then. 

Testing:
- [x] hs-tier1 - hs-tier4

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Commit messages:
 - Make UseVtableBasedCHA known to jtreg

Changes: https://git.openjdk.java.net/jdk/pull/4210/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4210&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267805
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4210.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4210/head:pull/4210

PR: https://git.openjdk.java.net/jdk/pull/4210