Fix class names in ApcUniversalClassLoader tests.
minor #10577 [ClassLoader] Fix class names in ApcUniversalClassLoader tests. (idn2104)

This PR was merged into the 2.3 branch.

Discussion
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[ClassLoader] Fix class names in ApcUniversalClassLoader tests.

[ClassLoader] These tests were failing due to a leading slash in the class name. Support for the leading slash in findFile was removed a while ago, but the Apc tests were not updated. See #10576 for more details.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #10576
| License       | MIT
| Doc PR        | N/A

Commits
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dc0f8f9 Fix class names in ApcUniversalClassLoader tests.