remove most uses of Isolate::Current in arch specific files

src/ia32/ic-ia32.cc

Index: src/ia32/ic-ia32.cc
diff --git a/src/ia32/ic-ia32.cc b/src/ia32/ic-ia32.cc
index 1e0f14e7687b1ed66000753311d99bab1acb3c5f..327ac57623e0bfab62191f68e09625ba1c5135e6 100644
--- a/src/ia32/ic-ia32.cc
+++ b/src/ia32/ic-ia32.cc
@@ -1306,7 +1306,7 @@ void LoadIC::GenerateMegamorphic(MacroAssembler* masm) {
   Code::Flags flags = Code::ComputeFlags(
       Code::STUB, MONOMORPHIC, Code::kNoExtraICState,
       Code::NORMAL, Code::LOAD_IC);
-  Isolate::Current()->stub_cache()->GenerateProbe(
+  masm->isolate()->stub_cache()->GenerateProbe(
       masm, flags, edx, ecx, ebx, eax);
 
   // Cache miss: Jump to runtime.
@@ -1425,8 +1425,8 @@ void StoreIC::GenerateMegamorphic(MacroAssembler* masm,
   Code::Flags flags = Code::ComputeFlags(
       Code::STUB, MONOMORPHIC, strict_mode,
       Code::NORMAL, Code::STORE_IC);
-  Isolate::Current()->stub_cache()->GenerateProbe(masm, flags, edx, ecx, ebx,
-                                                  no_reg);
+  masm->isolate()->stub_cache()->GenerateProbe(
+      masm, flags, edx, ecx, ebx, no_reg);
 
   // Cache miss: Jump to runtime.
   GenerateMiss(masm);