RFR: 8378298: Remove obsolete CDS string tests

[Matias Saavedra Silva]

On Fri, 20 Feb 2026 02:21:21 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> There are some very basic String test cases that came from early CDS development. They don't serve any purposes anymore as the functionalities are already covered by other test cases.
> 
> The methods of `WhiteBox.{areSharedStringsMapped, isSharedInternedString}` do not work for `AOTStreamedHeapLoader`, whose design doesn't distinguish between strings that came from the CDS archive or the app. The test cases that use these methods don't seem to be worth keeping.
> 
> `DumpSymbolAndStringTable` should be simplified to only test for `VM.stringtable` and `VM.symboltable`. The boiler-plate tests for `VM.systemdictionary` should be removed as we already have a more elaborate test: `serviceability/dcmd/vm/DictionaryStatsTest.java`.

LGTM!

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Marked as reviewed by matsaave (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/29834#pullrequestreview-3833225907