Remove FunctionType (#2510)

Function signatures were previously redundantly stored on Function
objects as well as on FunctionType objects. These two signature
representations had to always be kept in sync, which was error-prone
and needlessly complex. This PR takes advantage of the new ability of
Type to represent multiple value types by consolidating function
signatures as a pair of Types (params and results) stored on the
Function object.

Since there are no longer module-global named function types,
significant changes had to be made to the printing and emitting of
function types, as well as their parsing and manipulation in various
passes.

The C and JS APIs and their tests also had to be updated to remove
named function types.

1 files changed, 3 insertions, 3 deletions

diff --git a/test/passes/metrics_all-features.txt b/test/passes/metrics_all-features.txt
index ba772597d..cb8daf050 100644
--- a/test/passes/metrics_all-features.txt
+++ b/test/passes/metrics_all-features.txt
@@ -14,8 +14,8 @@ total
  drop           : 6       
  if             : 4       
 (module
- (type $0 (func (param i32)))
- (type $FUNCSIG$vii (func (param i32 i32)))
+ (type $i32_=>_none (func (param i32)))
+ (type $i32_i32_=>_none (func (param i32 i32)))
  (memory $0 256 256)
  (data (i32.const 0) "\ff\ef\0f\1f 0@P\99")
  (table $0 256 256 funcref)
@@ -23,7 +23,7 @@ total
  (global $glob i32 (i32.const 1337))
  (event $e0 (attr 0) (param i32))
  (event $e1 (attr 0) (param i32 i32))
- (func $ifs (; 0 ;) (type $0) (param $x i32)
+ (func $ifs (; 0 ;) (param $x i32)
   (local $y f32)
   (block $block0
    (if