refactor(tests): remove 9 stale duplicate test files under src/test/gvisual

These test files in Gvisual/src/test/gvisual/ are superseded by larger, more comprehensive versions under Gvisual/test/gvisual/ (the directory configured as <testSourceDirectory> in pom.xml). The old copies were dead code: Surefire only scans Gvisual/test/, and the CI workflow's hand-built JUnitCore runner does not list them either. Removing them eliminates confusing duplicates and reduces the test compilation footprint.

Files removed (active version has strictly more @test methods AND larger body in every case):

  BipartiteAnalyzerTest          orphan 20 -> active 43

  ChromaticPolynomialCalculatorTest  6 -> 22

  CommunityDetectorTest         18 -> 26

  CycleAnalyzerTest             34 -> 51

  GraphComplementAnalyzerTest    5 -> 14

  GraphMergerTest               18 -> 19

  KCoreDecompositionTest        16 -> 44

  PageRankAnalyzerTest          20 -> 77

  ShortestPathFinderTest        22 -> 29

DominatingSetAnalyzerTest and GraphProductCalculatorTest under src/test/ have *more* @test methods than the active versions; those need manual merge and are left in place for follow-up.

Author: sauravbhattacharya001