VM: Fix more places with isolate embedded into unoptimized code.

runtime/vm/intrinsifier_arm.cc

Index: runtime/vm/intrinsifier_arm.cc
diff --git a/runtime/vm/intrinsifier_arm.cc b/runtime/vm/intrinsifier_arm.cc
index a5b73df24ba730c8197ddc1bd4755b115d109abd..4cd8e6a66abef9013df761e959c0e09beb7f1ab9 100644
--- a/runtime/vm/intrinsifier_arm.cc
+++ b/runtime/vm/intrinsifier_arm.cc
@@ -2030,8 +2030,7 @@ void Intrinsifier::JSRegExp_ExecuteMatch(Assembler* assembler) {
 // On stack: user tag (+0).
 void Intrinsifier::UserTag_makeCurrent(Assembler* assembler) {
   // R1: Isolate.
-  Isolate* isolate = Isolate::Current();
-  __ LoadImmediate(R1, reinterpret_cast<uword>(isolate));
+  __ LoadIsolate(R1);
   // R0: Current user tag.
   __ ldr(R0, Address(R1, Isolate::current_tag_offset()));
   // R2: UserTag.
@@ -2047,21 +2046,15 @@ void Intrinsifier::UserTag_makeCurrent(Assembler* assembler) {
 
 
 void Intrinsifier::UserTag_defaultTag(Assembler* assembler) {
-  Isolate* isolate = Isolate::Current();
-  // Set return value to default tag address.
-  __ LoadImmediate(R0,
-         reinterpret_cast<uword>(isolate) + Isolate::default_tag_offset());
-  __ ldr(R0, Address(R0, 0));
+  __ LoadIsolate(R0);
+  __ ldr(R0, Address(R0, Isolate::default_tag_offset()));
   __ Ret();
 }
 
 
 void Intrinsifier::Profiler_getCurrentTag(Assembler* assembler) {
-  // R1: Default tag address.
-  Isolate* isolate = Isolate::Current();
-  __ LoadImmediate(R1, reinterpret_cast<uword>(isolate));
-  // Set return value to Isolate::current_tag_.
-  __ ldr(R0, Address(R1, Isolate::current_tag_offset()));
+  __ LoadIsolate(R0);
+  __ ldr(R0, Address(R0, Isolate::current_tag_offset()));
   __ Ret();
 }