test: Restore old behavior of timeout per script line (deephaven#6647)

Effectively increases the timeout for each command run - multiline
commands must be explicitly declared as such.

Follow-up DH-18632

Author: niloc132

web/client-api/src/test/java/io/deephaven/web/client/api/AbstractAsyncGwtTestCase.java

@@ -166,9 +166,21 @@ protected Promise<IdeSession> connect(TableSourceBuilder tables) {
     }
 
     private Promise<IdeSession> runAllScriptsInOrder(IdeSession session, List<String> code) {
-        String block = String.join("\n", code);
-        delayTestFinish(4000);
-        return session.runCode(block).then(ignore -> Promise.resolve(session));
+        Promise<IdeSession> result = Promise.resolve(session);
+        for (int i = 0; i < code.size(); i++) {
+            final int index = i;
+            result = result.then(ignore -> {
+                delayTestFinish(4000 + index);
+
+                return session.runCode(code.get(index));
+            }).then(r -> {
+                if (r.getError() != null) {
+                    return Promise.reject(r.getError());
+                }
+                return Promise.resolve(session);
+            });
+        }
+        return result;
     }
 
     public IThenable.ThenOnFulfilledCallbackFn<IdeSession, JsTable> table(String tableName) {

web/client-api/src/test/java/io/deephaven/web/client/api/widget/plot/ChartDataTestGwt.java

@@ -33,9 +33,9 @@ public class ChartDataTestGwt extends AbstractAsyncGwtTestCase {
                     "my_col_defs = {\"ID\": dht.int32, \"Value\": dht.string, \"Deleted\": dht.bool_}",
                     "ug = jpy.get_type('io.deephaven.engine.updategraph.impl.EventDrivenUpdateGraph').newBuilder('test').existingOrBuild()",
                     "exec_ctx = ExecutionContext(get_exec_ctx().j_object.withUpdateGraph(ug))",
-                    "with exec_ctx:",
-                    "    input = input_table(col_defs=my_col_defs, key_cols=\"ID\")",
-                    "    result = input.without_attributes('InputTable').where(\"!Deleted\").sort(\"ID\")");
+                    "with exec_ctx:\n" +
+                            "    input = input_table(col_defs=my_col_defs, key_cols=\"ID\")\n" +
+                            "    result = input.without_attributes('InputTable').where(\"!Deleted\").sort(\"ID\")");
 
     @Override
     public String getModuleName() {