RFR: 7801: Fix GHA that is broken due to OpenJDK Update 11.0.15

[Christoph Langer]

OpenJDK 11.0.15 has introduced a regression that breaks the JMC build on Windows (with JDK-8278356). It will be fixed in OpenJDK 11.0.16 with JDK-8285445.

For now we can workaround the problem by pinning to OpenJDK 11.0.14 in the GHA workflow which should be fine from a security perspective.

I also experimented with adding `-Djdk.io.File.enableADS=true` which is what JDK-8285445 effectively does but to no avail.

The change updates to actions/setup-java at v2 and sets the JDK distribution in use to Temurin.

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

Commit messages:
 - Fix GHA

Changes: https://git.openjdk.java.net/jmc/pull/402/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=402&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-7801
  Stats: 9 lines in 1 file changed: 3 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jmc/pull/402.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/402/head:pull/402

PR: https://git.openjdk.java.net/jmc/pull/402