Use TopologicalSort::minSort to order rec groups (#6892)

Rec groups need to be topologically sorted for the output module to be
valid, but the specific order of rec groups also affects the module size
because types at lower indices requires fewer bytes to reference. We
previously optimized for code size when gathering types by sorting the
list of groups before doing the topological sort. This was brittle,
though, and depended on implementation details of the topological sort
to be correct.

Replace the old topological sort with use of the new
`TopologicalSort::minSort` utility, which is a more principled method of
achieving a minimal topological sort with respect to some comparator.
Also draw inspiration from ReorderGlobals and apply an exponential
factor to take the users of a rec group into account when determining
its weight.

1 files changed, 2 insertions, 2 deletions

diff --git a/test/lit/passes/vacuum-gc.wast b/test/lit/passes/vacuum-gc.wast
index a59b2da1e..dd4934e0a 100644
--- a/test/lit/passes/vacuum-gc.wast
+++ b/test/lit/passes/vacuum-gc.wast
@@ -38,7 +38,7 @@
     )
   )
 
-  ;; CHECK:      (func $vacuum-nonnull (type $0)
+  ;; CHECK:      (func $vacuum-nonnull (type $1)
   ;; CHECK-NEXT:  (nop)
   ;; CHECK-NEXT: )
   (func $vacuum-nonnull
@@ -101,7 +101,7 @@
     )
   )
 
-  ;; CHECK:      (func $dropped-calls (type $0)
+  ;; CHECK:      (func $dropped-calls (type $1)
   ;; CHECK-NEXT:  (block
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (call $helper-i32)