[wasm] Change the constant kV8MaxWasmMemoryPages to a command line flag.

test/fuzzer/wasm-asmjs.cc

Index: test/fuzzer/wasm-asmjs.cc
diff --git a/test/fuzzer/wasm-asmjs.cc b/test/fuzzer/wasm-asmjs.cc
index d3341fa5b30135f52c6c184c0fb76dbc54f466d4..6d95db788c1a4676c102c9d8825b62ec63158631 100644
--- a/test/fuzzer/wasm-asmjs.cc
+++ b/test/fuzzer/wasm-asmjs.cc
@@ -17,6 +17,8 @@
 #include "test/fuzzer/fuzzer-support.h"
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  unsigned int flag_value = v8::internal::FLAG_wasm_max_mem_pages;
+  v8::internal::FLAG_wasm_max_mem_pages = 32;
   v8_fuzzer::FuzzerSupport* support = v8_fuzzer::FuzzerSupport::Get();
   v8::Isolate* isolate = support->GetIsolate();
   v8::internal::Isolate* i_isolate =
@@ -35,5 +37,6 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   v8::internal::wasm::testing::CompileAndRunWasmModule(
       i_isolate, data, data + size,
       v8::internal::wasm::ModuleOrigin::kAsmJsOrigin);
+  v8::internal::FLAG_wasm_max_mem_pages = flag_value;
   return 0;
 }