Move Java 8 indy spec:ji and force compilation

This moves the indy-enabled Java 8 spec:ji run to the "latest LTS"
group (currently 21-ea) and adds additional flags there to force
compilation.

The latter change is needed in order for some types of tests to
fully compile (like rspec specs, which usually have only blocks
down to the root of the script). Both flags are required to force
compilation of whole files (e.g. specs) or individual methods and
blocks (if whole file fails or new methods are evaluated at
runtime). This should help catch more indy issues.

.github/workflows/ci.yml

@@ -81,14 +81,14 @@ jobs:
 
     strategy:
       matrix:
-        target: ['test:mri:core:jit', 'test:jruby:jit', 'spec:compiler', 'spec:ruby:fast:jit']
+        target: ['test:mri:core:jit', 'test:jruby:jit', 'spec:compiler', 'spec:ruby:fast:jit', 'spec:ji']
         java-version: ['21-ea']
       fail-fast: false
 
     name: rake ${{ matrix.target }} (Java ${{ matrix.java-version }} +indy)
 
     env:
-      JRUBY_OPTS: '-Xcompile.invokedynamic'
+      JRUBY_OPTS: '-Xcompile.invokedynamic -X+C -Xjit.threshold=0'
 
     steps:
       - name: Bootstrap build
@@ -153,27 +153,6 @@ jobs:
         env:
           PHASE: 'package ${{ matrix.package-flags }}'
 
-  ji-specs-8-indy:
-    runs-on: ubuntu-latest
-
-    strategy:
-      fail-fast: false
-
-    env:
-      JRUBY_OPTS: '-Xcompile.invokedynamic'
-
-    steps:
-      - name: Bootstrap build
-        uses: jruby/jruby-ci-build@v1
-      - name: set up java 8
-        uses: actions/setup-java@v3
-        with:
-          distribution: 'zulu'
-          java-version: 8
-          cache: 'maven'
-      - name: rake spec:ji
-        run: bin/jruby -S rake spec:ji
-
   regression-specs-jit:
     runs-on: ubuntu-latest
 
@@ -415,7 +394,7 @@ jobs:
     permissions:
       contents: none
     if: ${{ github.ref == 'refs/heads/master' || github.ref == 'refs/heads/jruby-9.3' }}
-    needs: [mvn-test, mvn-test-8, mvn-test-windows, dependency-check, rake-test, rake-test-17-indy, rake-test-8, test-versions, sequel, concurrent-ruby, jruby-tests-dev, ji-specs-8-indy, regression-specs-jit, mvn-test-m1]
+    needs: [mvn-test, mvn-test-8, mvn-test-windows, dependency-check, rake-test, rake-test-17-indy, rake-test-8, test-versions, sequel, concurrent-ruby, jruby-tests-dev, regression-specs-jit, mvn-test-m1]
     uses: jruby/jruby/.github/workflows/snapshot-publish.yml@6cd0d4d96d9406635183d81cf91acc82cd78245f
     secrets:
       SONATYPE_USERNAME: ${{ secrets.SONATYPE_USERNAME }}