[wasm-simd] Use kWasmStmt as invalid type in function sig

0x7b is the encoding for SIMD v128 types, so it will become valid when
we turn SIMD on by default. Use kWasmStmt (0x40) instead, it is not a
valid in the function signature position (which requires a value type).

Bug: v8:11511
Change-Id: Ife152e81d831a059a0122f9255897d97b5dc4fc9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2739054
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73232}

test/mjsunit/wasm/streaming-error-position.js

@@ -390,7 +390,7 @@ function testErrorPosition(bytes, pos, message) {
       1,                      // number of types
       kWasmFunctionTypeForm,  // type
       1,                      // number of parameter
-      0x7b,                   // invalid type
+      kWasmStmt,              // invalid type
       0                       // number of returns
   ]);