gn format: fix comments at end of blocks

tools/gn/format_test_data/017.golden

Index: tools/gn/format_test_data/017.golden
diff --git a/tools/gn/format_test_data/017.golden b/tools/gn/format_test_data/017.golden
new file mode 100644
index 0000000000000000000000000000000000000000..2a658c61b0cb49f81a1072cf128acc05f14b149e
--- /dev/null
+++ b/tools/gn/format_test_data/017.golden
@@ -0,0 +1,19 @@
+executable(
+  "win"  # Suffix comment on arg.
+
+  # And a strangely positioned line comment for some reason
+) {
+  defines = []  # Defines comment, suffix at end position.
+
+  deps = [
+    # Deps comment, should be forced multiline.
+  ]
+
+  sources = [
+    "a.cc",
+
+    # End of single sources comment, should be forced multiline.
+  ]
+
+  # End of block comment.
+}