[wasm] Add instruction cache flush for wrapper table

Add instruction cache flish for wrapper table in module compiler
instance builder. This fixes several failures in mjsunit/wasm
and mjsunit/asm test suites on some MIPS boards.

Bug: 
Change-Id: Ia8b640ad73a078d29f458d55663606dbbe8e387c
Reviewed-on: https://chromium-review.googlesource.com/697807Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Ivica Bogosavljevic <ivica.bogosavljevic@imgtec.com>
Cr-Commit-Position: refs/heads/master@{#48280}

src/wasm/module-compiler.cc

@@ -1931,6 +1931,7 @@ MaybeHandle<WasmInstanceObject> InstanceBuilder::Build() {
   code_specialization.ApplyToWholeInstance(*instance, SKIP_ICACHE_FLUSH);
 
   FlushICache(isolate_, code_table);
+  FlushICache(isolate_, wrapper_table);
 
   //--------------------------------------------------------------------------
   // Unpack and notify signal handler of protected instructions.