Fix references in forms writing mode manual tests (#37118)

I broke them earlier when moving them in this subdirectory.
diff --git a/css/css-writing-modes/support/form-controls-slr.png b/css/css-writing-modes/forms/manual/support/form-controls-slr.png
similarity index 100%
rename from css/css-writing-modes/support/form-controls-slr.png
rename to css/css-writing-modes/forms/manual/support/form-controls-slr.png
Binary files differ
diff --git a/css/css-writing-modes/support/form-controls-srl.png b/css/css-writing-modes/forms/manual/support/form-controls-srl.png
similarity index 100%
rename from css/css-writing-modes/support/form-controls-srl.png
rename to css/css-writing-modes/forms/manual/support/form-controls-srl.png
Binary files differ
diff --git a/css/css-writing-modes/support/form-controls-vlr.png b/css/css-writing-modes/forms/manual/support/form-controls-vlr.png
similarity index 100%
rename from css/css-writing-modes/support/form-controls-vlr.png
rename to css/css-writing-modes/forms/manual/support/form-controls-vlr.png
Binary files differ
diff --git a/css/css-writing-modes/support/vertical-form.png b/css/css-writing-modes/forms/manual/support/vertical-form.png
similarity index 100%
rename from css/css-writing-modes/support/vertical-form.png
rename to css/css-writing-modes/forms/manual/support/vertical-form.png
Binary files differ