fix(test): prevent data file clobbering when running --suite=all

When running `make test` (--suite=all), the load and ldbc download
blocks in t/t.go shared the same *tmp directory. The ldbc block's
MakeDirEmpty call wiped files downloaded by the load block, causing
systest/1million to fail with missing schema files.

Hoist directory initialization above both download blocks so
MakeDirEmpty runs exactly once. Both datasets coexist in the same
directory since their filenames don't overlap. Also use a dedicated
subdirectory (dgraph-test-data) instead of bare os.TempDir() to
avoid wiping the system temp directory.

Add testSuiteContainsAny() helper to replace repeated
testSuiteContains("x") || testSuiteContains("y") patterns.

Author: mlwelles

t/t.go

@@ -899,6 +899,15 @@ func testSuiteContains(suite string) bool {
 	return false
 }
 
+func testSuiteContainsAny(suites ...string) bool {
+	for _, suite := range suites {
+		if testSuiteContains(suite) {
+			return true
+		}
+	}
+	return false
+}
+
 func isValidPackageForSuite(pkg string) bool {
 	valid := false
 	if testSuiteContains("all") {
@@ -1211,19 +1220,18 @@ func run() error {
 	go func() {
 		defer close(testCh)
 		valid := getPackages()
-
-		if testSuiteContains("load") || testSuiteContains("all") {
-			if *tmp == "" {
-				*tmp = os.TempDir()
-			}
+		// in "all" mode we can download both data files and
+		// ldbc files into the same directory, no duplicated
+		// filenames between the two
+		needsData := testSuiteContainsAny("load", "ldbc", "all")
+		if needsData && *tmp == "" {
+			*tmp = filepath.Join(os.TempDir(), "dgraph-test-data")
 			x.Check(testutil.MakeDirEmpty([]string{*tmp}))
+		}
+		if testSuiteContainsAny("load", "all") {
 			downloadDataFiles()
 		}
-		if testSuiteContains("ldbc") || testSuiteContains("all") {
-			if *tmp == "" {
-				*tmp = filepath.Join(os.TempDir(), "/ldbcdata")
-			}
-			x.Check(testutil.MakeDirEmpty([]string{*tmp}))
+		if testSuiteContainsAny("ldbc", "all") {
 			downloadLDBCFiles()
 		}
 		for i, task := range valid {