Simplify SymLink creation in eclipse.core.tests

[HannesWell]

As discussed in #755 (comment).

[github-actions]

Test Results

 1 653 files   -  81   1 653 suites   - 81   1h 27m 27s ⏱️ - 6m 25s
 3 820 tests  - 153   3 791 ✅  - 160   22 💤 ±0   7 ❌ + 7 
12 057 runs   - 459  11 879 ✅  - 476  161 💤 ±0  17 ❌ +17 

For more details on these failures, see this check.

Results for commit 1439588. ± Comparison against base commit 80fd47a.

This pull request removes 153 tests.

AllCompareTests AsyncExecTests ‑ testCancelOnRequeue
AllCompareTests AsyncExecTests ‑ testQueueAdd
AllCompareTests AsyncExecTests ‑ testWorker
AllCompareTests CompareFileRevisionEditorInputTest ‑ testPrepareCompareInputWithNonLocalResourceTypedElements
AllCompareTests CompareUIPluginTest ‑ testFindContentViewerDescriptorForTextType_StreamAccessor
AllCompareTests CompareUIPluginTest ‑ testFindContentViewerDescriptor_TextType_NotStreamAccessor
AllCompareTests CompareUIPluginTest ‑ testFindContentViewerDescriptor_UnknownType
AllCompareTests ContentMergeViewerTest ‑ testFFFX
AllCompareTests ContentMergeViewerTest ‑ testFFTX
AllCompareTests ContentMergeViewerTest ‑ testFFXF
…

♻️ This comment has been updated with latest results.