ci: equivalence — pass output-directory (not database/) as java DbFork -d

Third latent bug the vacuous skip had hidden, now that the gate runs:
java DbFork failed with

  IO error: .../002/database/database/witness/LOCK: No such file or directory
                          ^^^^^^^^^^^^^^^^ doubled

The test passed `-d <scratch>/database`, but java DbFork's -d is the
output-directory (the PARENT of database/) — DbTool.getDB appends
`database/<store>` internally (DbFork.java:120). So java looked in
<scratch>/database/database/<store> and failed to open the LOCK.

The Go side already uses the parent (Apply(scratchGo) opens
scratchGo/database/<store>), and diffStore reads via
OpenLevelDB(<parent>, store) — so only java's -d was wrong. This was
never exercised before because the gate skipped on the missing jar.

Fix: pass scratchJava (the output-directory parent) as -d. The Go
Apply ran cleanly in the failed run (its TRC20-skip logs are present);
this unblocks java so the run reaches the actual 8-store diff.

Author: barbatos2011

internal/dbfork/equivalence_test.go

@@ -146,7 +146,15 @@ func TestEquivalence_GoVsJava(t *testing.T) {
 		// store readers. Configurable via DBFORK_JAVA_HEAP env var.
 		javaHeapFlag(),
 		"-jar", javaJar, "db", "fork",
-		"-d", filepath.Join(scratchJava, "database"),
+		// -d is the output-directory (the PARENT of database/), NOT the
+		// database/ dir itself: java DbFork's DbTool.getDB appends
+		// `database/<store>` internally (DbFork.java:120 -> DbTool). The
+		// Go side mirrors this — Apply(scratchGo) opens
+		// scratchGo/database/<store>. Passing scratchJava/database here
+		// made java look in scratchJava/database/database/<store> and
+		// fail to open the LOCK. (Latent until the gate stopped
+		// vacuously skipping — the java path was never exercised.)
+		"-d", scratchJava,
 		"-c", forkConfPath,
 	}
 	if len(cfg.Witnesses) == 0 {