Clean-up and simplify usage of E4's XPathContext in E4-tools

[HannesWell]

No description provided.

[github-actions]

Test Results

 6 files   -    279   6 suites   - 279   13s ⏱️ - 48m 15s
 4 tests  -  3 604   4 ✅  -  3 528  0 💤  -  76  0 ❌ ±0 
12 runs   - 11 004  12 ✅  - 10 773  0 💤  - 231  0 ❌ ±0 

Results for commit 04874ac. ± Comparison against base commit 975f72b.

This pull request removes 3604 tests.

AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.DependencyManagerTest ‑ testFindRequirementsClosure_importPackage
AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.DependencyManagerTest ‑ testFindRequirementsClosure_includeFragments
AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.DependencyManagerTest ‑ testFindRequirementsClosure_includeFragmentsProvidingPackages
AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.DependencyManagerTest ‑ testFindRequirementsClosure_includeNonTestFragments
AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.DependencyManagerTest ‑ testFindRequirementsClosure_includeOptional
AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.DependencyManagerTest ‑ testFindRequirementsClosure_requireBundle
AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.DependencyManagerTest ‑ testFindRequirementsClosure_requireBundle2
AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.DependencyManagerTest ‑ testFindRequirementsClosure_requireDifferentVersions
AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.DependencyManagerTest ‑ testFindRequirementsClosure_requiredCapability
AllPDETests org.eclipse.pde.core.tests.internal.AllPDECoreTests org.eclipse.pde.core.tests.internal.WorkspaceModelManagerTest ‑ testBundleRootHandling_bundleRootChangedFromDefaultToOthersAndReverse
…

[HannesWell]

This should await and use the final result of

• [E4 XPath] Add new API in EModelService to find elements via Xpath and deprecate E4-XPath bundle for removal eclipse-platform/eclipse.platform.ui#2789