gn format: fix comments at end of blocks

tools/gn/format_test_data/017.gn

Index: tools/gn/format_test_data/017.gn
diff --git a/tools/gn/format_test_data/017.gn b/tools/gn/format_test_data/017.gn
new file mode 100644
index 0000000000000000000000000000000000000000..225ae2fe30c472e3c0dfc65fc3143ceeb4dd1cca
--- /dev/null
+++ b/tools/gn/format_test_data/017.gn
@@ -0,0 +1,15 @@
+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.
+}