Remember deopt-id -> context-level mappings in var descriptors.

runtime/vm/flow_graph_compiler_mips.cc

Index: runtime/vm/flow_graph_compiler_mips.cc
diff --git a/runtime/vm/flow_graph_compiler_mips.cc b/runtime/vm/flow_graph_compiler_mips.cc
index afaf6bce035cf54789df184b1758dadc0f5b1d29..08773fdc9a8d0a9922750807f3db0fa141cc7bba 100644
--- a/runtime/vm/flow_graph_compiler_mips.cc
+++ b/runtime/vm/flow_graph_compiler_mips.cc
@@ -1362,7 +1362,8 @@ Condition FlowGraphCompiler::EmitEqualityRegConstCompare(
     Register reg,
     const Object& obj,
     bool needs_number_check,
-    TokenPosition token_pos) {
+    TokenPosition token_pos,
+    intptr_t deopt_id) {
   __ Comment("EqualityRegConstCompare");
   ASSERT(!needs_number_check ||
          (!obj.IsMint() && !obj.IsDouble() && !obj.IsBigint()));
@@ -1379,10 +1380,7 @@ Condition FlowGraphCompiler::EmitEqualityRegConstCompare(
       __ BranchLinkPatchable(
           *StubCode::UnoptimizedIdenticalWithNumberCheck_entry());
     }
-    if (token_pos.IsReal()) {
-      AddCurrentDescriptor(RawPcDescriptors::kRuntimeCall, Thread::kNoDeoptId,
-                           token_pos);
-    }
+    AddCurrentDescriptor(RawPcDescriptors::kRuntimeCall, deopt_id, token_pos);
     __ Comment("EqualityRegConstCompare return");
     // Stub returns result in CMPRES1 (if it is 0, then reg and obj are equal).
     __ lw(reg, Address(SP, 1 * kWordSize));      // Restore 'reg'.
@@ -1396,11 +1394,11 @@ Condition FlowGraphCompiler::EmitEqualityRegConstCompare(
 }
 
 
-Condition FlowGraphCompiler::EmitEqualityRegRegCompare(
-    Register left,
-    Register right,
-    bool needs_number_check,
-    TokenPosition token_pos) {
+Condition FlowGraphCompiler::EmitEqualityRegRegCompare(Register left,
+                                                       Register right,
+                                                       bool needs_number_check,
+                                                       TokenPosition token_pos,
+                                                       intptr_t deopt_id) {
   __ Comment("EqualityRegRegCompare");
   if (needs_number_check) {
     __ addiu(SP, SP, Immediate(-2 * kWordSize));