gn format: add call wrapping

tools/gn/format_test_data/022.golden

Index: tools/gn/format_test_data/022.golden
diff --git a/tools/gn/format_test_data/022.golden b/tools/gn/format_test_data/022.golden
new file mode 100644
index 0000000000000000000000000000000000000000..4042c9b400fda4ecd0c366881c57fd28ca47c7a5
--- /dev/null
+++ b/tools/gn/format_test_data/022.golden
@@ -0,0 +1,7 @@
+executable(something[0]) {
+  if (weeeeee.stuff) {
+    x = a.b

[brettw, 2014/10/01 23:52:38]

This is one case where I think I would like to change in the future. In some
cases it's nice to have blank lines separating assignments for clarity, and in
other cases not. Like for chromium_code config, I would put the subtraction and
addition one-after-another. Or public_deps and deps. And some targets are two
variables only and the extra whitespace looks silly.

I wonder if it can preserve this?

+
+    y = a[8]
+  }
+}