Remove unused function GeneratePreEntryCode from ia32 code generator.

vm/opt_code_generator_ia32.cc

Index: vm/opt_code_generator_ia32.cc
===================================================================
--- vm/opt_code_generator_ia32.cc	(revision 8186)
+++ vm/opt_code_generator_ia32.cc	(working copy)
@@ -369,14 +369,6 @@
 }
 
 
-// Check for stack overflow.
-// Note that first 5 bytes may be patched with a jump.
-// TODO(srdjan): Add check that no object is inlined in the first
-// 5 bytes (length of a jump instruction).
-void OptimizingCodeGenerator::GeneratePreEntryCode() {
-}
-
-
 void OptimizingCodeGenerator::CallDeoptimize(intptr_t node_id,
                                              intptr_t token_index) {
   __ call(&StubCode::DeoptimizeLabel());