[wasm][cleanup] Turn CALL_BUILTIN into a function

Functions are easier to maintain and to debug than macros, hence
transform the macro into a function.

R=thibaudm@chromium.org

Bug: v8:11384
Change-Id: I6a5a836e14c33dc3c2240b6b06edcb05c6514710
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2704074
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72870}

src/compiler/wasm-compiler.h

@@ -553,7 +553,6 @@ class WasmGraphBuilder {
   Node* BuildCallRef(uint32_t sig_index, Vector<Node*> args, Vector<Node*> rets,
                      CheckForNull null_check, IsReturnCall continuation,
                      wasm::WasmCodePosition position);
-  Node* GetBuiltinPointerTarget(int builtin_id);
 
   Node* BuildF32CopySign(Node* left, Node* right);
   Node* BuildF64CopySign(Node* left, Node* right);