chore(e2e benchmark test): allows selection of only one test (#3618)

Closes #3617

Before this PR, you could run:
```
 go run ./test/e2e/benchmark
test-e2e-benchmark2024/06/24 13:02:13 No particular test specified. Running all tests.
test-e2e-benchmark2024/06/24 13:02:13 go run ./test/e2e/benchmark <test_name> to run a specific test
test-e2e-benchmark2024/06/24 13:02:13 Valid tests are: TwoNodeSimple
```
and it would start running all the benchmark tests. However, after this
PR, it will require user to specify the test name:
```
go run ./test/e2e/benchmark                       
test-e2e-benchmark2024/06/24 13:26:24 No test is specified.
test-e2e-benchmark2024/06/24 13:26:24 Usage: go run ./test/e2e/benchmark <test_name>
test-e2e-benchmark2024/06/24 13:26:24 Valid tests are: TwoNodeSimple

```

test/e2e/benchmark/main.go

@@ -14,26 +14,28 @@ func main() {
 	}
 
 	// check the test name passed as an argument and run it
-	specificTestFound := false
-	for _, arg := range os.Args[1:] {
-		for _, test := range tests {
-			if test.Name == arg {
-				runTest(logger, test)
-				specificTestFound = true
-				break
-			}
-		}
-	}
-
-	if !specificTestFound {
-		logger.Println("No particular test specified. Running all tests.")
-		logger.Println("go run ./test/e2e/benchmark <test_name> to run a specific test")
+	if len(os.Args) < 2 {
+		logger.Println("No test is specified.")
+		logger.Println("Usage: go run ./test/e2e/benchmark <test_name>")
 		logger.Printf("Valid tests are: %s\n\n", getTestNames(tests))
-		// if no specific test is passed, run all tests
-		for _, test := range tests {
+		return
+
+	}
+	found := false
+	testName := os.Args[1]
+	for _, test := range tests {
+		if test.Name == testName {
+			found = true
 			runTest(logger, test)
+			break
 		}
 	}
+	if !found {
+		logger.Printf("Invalid test name: %s\n", testName)
+		logger.Printf("Valid tests are: %s\n", getTestNames(tests))
+		logger.Println("Usage: go run ./test/e2e/benchmark <test_name>")
+
+	}
 }
 
 type TestFunc func(*log.Logger) error