cmd/compile: rotate phase's title 180 degrees in ssa/html.go

Modify phase's title according to html.go:122 TODO.

Fixes #41098

Change-Id: I58fa365e718600aaaa0a72cce72d35a484cde8b8
Reviewed-on: https://go-review.googlesource.com/c/go/+/251657
Reviewed-by: Bradford Lamson-Scribner <brad.lamson@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
diff --git a/src/cmd/compile/internal/ssa/html.go b/src/cmd/compile/internal/ssa/html.go
index ba37a80..1c70b64 100644
--- a/src/cmd/compile/internal/ssa/html.go
+++ b/src/cmd/compile/internal/ssa/html.go
@@ -119,7 +119,8 @@
 }
 
 td.collapsed div {
-    /* TODO: Flip the direction of the phase's title 90 degrees on a collapsed column. */
+    text-align: right;
+    transform: rotate(180deg);
     writing-mode: vertical-lr;
     white-space: pre;
 }