istio-interop-testing: increase deadline to 5 sec to avoid deadline issue on aarch64 (grpc#9497)

Author: sanjaypujare

istio-interop-testing/src/test/java/io/grpc/testing/istio/EchoTestServerTest.java

@@ -206,7 +206,7 @@ public void forwardEchoTest() throws IOException, InterruptedException {
  ForwardEchoRequest.newBuilder()
  .setCount(COUNT_OF_REQUESTS_TO_FORWARD)
  .setQps(100)
- .setTimeoutMicros(2000_000L) // 2000 millis
+ .setTimeoutMicros(5000_000L) // 5000 millis
  .setUrl("grpc://localhost:" + port2)
  .addHeaders(
  Header.newBuilder().setKey("test-key1").setValue("test-value1").build())