[ic] Fix megamorphic stub cache probing on some platforms.

src/ic/x87/stub-cache-x87.cc

Index: src/ic/x87/stub-cache-x87.cc
diff --git a/src/ic/x87/stub-cache-x87.cc b/src/ic/x87/stub-cache-x87.cc
index e2d994a466700a15f30196088a38282ae0d35632..7c5b30abb8ff57620b5a0ba9a18a8bb29663a017 100644
--- a/src/ic/x87/stub-cache-x87.cc
+++ b/src/ic/x87/stub-cache-x87.cc
@@ -17,7 +17,8 @@ namespace internal {
 static void ProbeTable(StubCache* stub_cache, MacroAssembler* masm,
                        Code::Kind ic_kind, Code::Flags flags,
                        StubCache::Table table, Register name, Register receiver,
-                       // Number of the cache entry pointer-size scaled.
+                       // The offset is scaled by 4, based on
+                       // kCacheIndexShift, which is two bits
                        Register offset, Register extra) {
   ExternalReference key_offset(stub_cache->key_reference(table));
   ExternalReference value_offset(stub_cache->value_reference(table));