cmd/compile: prevent infinite recursion printing types in Fatalf

Updates #20162

Change-Id: Ie289bae0d0be8430e492ac73fd6e6bf36991d4a1
Reviewed-on: https://go-review.googlesource.com/42130Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/align.go

@@ -183,6 +183,11 @@ func dowidth(t *types.Type) {
 	}
 
 	if sizeCalculationDisabled {
+		if t.Broke() {
+			// break infinite recursion from Fatal call below
+			return
+		}
+		t.SetBroke(true)
 		Fatalf("width not calculated: %v", t)
 	}