[jdk8u-dev] RFR: 8294863: Enable initial tier1 testing in GHA for JDK8

[zzambers]

This change adds support for tier1 testing in github actions by fixing workflow to work  with JDK8. (Changes were needed due to build system difference compared to newer JDK.) Support for running tests is done for all systems. This includes adding code to run tests on windows x86, which was missing. Currently only jdk_tier1 on linuxes and macos is enabled, as currently only this is passing without failures (see details lower). Testing on windows is currently disabled (no tier1 groups are passing there currently). Disabled tests can be easily enabled once, they are fixed. Ultimate goal is of course to run all tier1 groups (jdk_tier1, langtools_tier1, hotspot_tier1) on all platforms.

**Tier1 status:**

jdk_tier1
- enabled on linuxes and macos (passes there)
- disabled on on windows, where `com/sun/jdi/*.sh` shell tests are currently failing

langtools_tier1
- disabled everywhere
- 1 failure: `tools/javac/diags/CheckExamples.java` (all platforms, see: [1])

hotspot_tier1
- disabled everywhere
- there are several faiures of `compiler/rtm/*` tests. These tests seem to broken on some systems (see: [2]), including machines used by GHA. Some tests are already excluded [3], but there are few more. Also exclusions were made only on x64 but it also affects x86.
- on x86 (32-bit) platforms there are few additional failures

[1] https://bugs.openjdk.org/browse/JDK-8265527
[2] https://bugs.openjdk.org/browse/JDK-8183263
[3] https://bugs.openjdk.org/browse/JDK-8226899

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Commit messages:
 - Enable initial tier1 testing

Changes: https://git.openjdk.org/jdk8u-dev/pull/131/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=131&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294863
  Stats: 484 lines in 1 file changed: 170 ins; 212 del; 102 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/131.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev pull/131/head:pull/131

PR: https://git.openjdk.org/jdk8u-dev/pull/131