[wasm] Avoid spread of huge arrays in module builder

I just ran into this when creating a test case. The huge spread caused
a RangeError (stack overflow). It's not causing problems for the tests
we currently have, but let's fix it anyway.

R=ahaas@chromium.org

Change-Id: Ib67f059f2981ccc6239ba4ae05611e20eb3aa191
Reviewed-on: https://chromium-review.googlesource.com/c/1329177
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57429}

test/mjsunit/wasm/wasm-module-builder.js

@@ -74,7 +74,8 @@ class Binary extends Array {
     // Emit section length.
     this.emit_u32v(section.length);
     // Copy the temporary buffer.
-    this.push(...section);
+    // Avoid spread because {section} can be huge.
+    for (let b of section) this.push(b);
   }
 }
 
@@ -209,7 +210,10 @@ class WasmModuleBuilder {
     name = this.stringToBytes(name);
     var length = new Binary();
     length.emit_u32v(name.length + bytes.length);
-    this.explicit.push([0, ...length, ...name, ...bytes]);
+    var section = [0, ...length, ...name];
+    // Avoid spread because {bytes} can be huge.
+    for (var b of bytes) section.push(b);
+    this.explicit.push(section);
   }
 
   addType(type) {