chore: revert custom index in favor of key_Split

Signed-off-by: Keith Zantow <keith.zantow@anchore.com>

internal/file/zip_file_traversal_test.go

@@ -305,45 +305,6 @@ func TestSafeJoin(t *testing.T) {
 			expected:     "",
 			errAssertion: assertErrorAs(&errZipSlipDetected{}),
 		},
-		// a legitimate nested path, several components deep
-		{
-			prefix: "/a/place",
-			args: []string{
-				"lib",
-				"sub",
-				"file.txt",
-			},
-			expected:     "/a/place/lib/sub/file.txt",
-			errAssertion: assert.NoError,
-		},
-		// the prefix itself is inside the prefix
-		{
-			prefix: "/a/place",
-			args: []string{
-				".",
-			},
-			expected:     "/a/place",
-			errAssertion: assert.NoError,
-		},
-		// siblings that share the prefix as a STRING are not inside it. A string-prefix comparison
-		// accepted these, so an archive entry could write into a directory next to the one it was
-		// being extracted into.
-		{
-			prefix: "/a/place",
-			args: []string{
-				"../place-evil/x",
-			},
-			expected:     "",
-			errAssertion: assertErrorAs(&errZipSlipDetected{}),
-		},
-		{
-			prefix: "/tmp/syft-archive-abc/contents",
-			args: []string{
-				"../contents-evil/x",
-			},
-			expected:     "",
-			errAssertion: assertErrorAs(&errZipSlipDetected{}),
-		},
 	}
 
 	for _, test := range tests {