Add Roundtrip Tests for both instructions

crates/tests/tests/round_trip/return_call.wat

@@ -0,0 +1,20 @@
+(module
+  (func $g (result i32)
+    i32.const 42
+    return)
+  (func $f (result i32)
+    return_call $g)
+  (export "f" (func $f)))
+
+(; CHECK-ALL:
+  (module
+    (type (;0;) (func (result i32)))
+    (func $g (;0;) (type 0) (result i32)
+      i32.const 42
+      return
+    )
+    (func $f (;1;) (type 0) (result i32)
+      return_call $g
+    )
+    (export "f" (func $f))
+;)

crates/tests/tests/round_trip/return_call_indirect.wat

@@ -0,0 +1,18 @@
+(module
+  (type (func (result i32)))
+  (table 1 funcref)
+  (func (export "a") (param i32) (result i32)
+    local.get 0
+    return_call_indirect (type 0)))
+
+(; CHECK-ALL:
+  (module
+    (type (;0;) (func (result i32)))
+    (type (;1;) (func (param i32) (result i32)))
+    (func (;0;) (type 1) (param i32) (result i32)
+      local.get 0
+      return_call_indirect (type 0)
+    )
+    (table (;0;) 1 funcref)
+    (export "a" (func 0))
+;)