Make `Ord Literal` deterministic (#19438)

Previously, non-determinism arising from a use of `uniqCompareFS` in
`cmpLit` potentially crept into `CoreMap`, which we expect to behave
deterministically.

So we simply use `lexicalCompareFS` now.

Fixes #19438.

compiler/GHC/Types/Literal.hs

@@ -869,7 +869,7 @@ cmpLit (LitString    a)     (LitString     b)     = a `compare` b
 cmpLit (LitNullAddr)        (LitNullAddr)         = EQ
 cmpLit (LitFloat     a)     (LitFloat      b)     = a `compare` b
 cmpLit (LitDouble    a)     (LitDouble     b)     = a `compare` b
-cmpLit (LitLabel     a _ _) (LitLabel      b _ _) = a `uniqCompareFS` b
+cmpLit (LitLabel     a _ _) (LitLabel      b _ _) = a `lexicalCompareFS` b
 cmpLit (LitNumber nt1 a)    (LitNumber nt2  b)
   | nt1 == nt2 = a   `compare` b
   | otherwise  = nt1 `compare` nt2