Fix lazy deoptimization from deferred code.

runtime/vm/flow_graph_compiler_arm.cc

Index: runtime/vm/flow_graph_compiler_arm.cc
diff --git a/runtime/vm/flow_graph_compiler_arm.cc b/runtime/vm/flow_graph_compiler_arm.cc
index b4df97c4b0ca2491d393f3f4e2d04da26ad692ff..3c3b1eaf591f4e498de46c44eb68e4e9a45c0f59 100644
--- a/runtime/vm/flow_graph_compiler_arm.cc
+++ b/runtime/vm/flow_graph_compiler_arm.cc
@@ -13,6 +13,7 @@
 #include "vm/dart_entry.h"
 #include "vm/deopt_instructions.h"
 #include "vm/il_printer.h"
+#include "vm/instructions.h"
 #include "vm/locations.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
@@ -1109,6 +1110,13 @@ void FlowGraphCompiler::CompileGraph() {
   GenerateDeferredCode();
 
   if (is_optimizing()) {
+    // Leave enough space for patching in case of lazy deoptimization from
+    // deferred code.
+    for (intptr_t i = 0;
+         i < CallPattern::DeoptCallPatternLengthInInstructions();
+         ++i) {
+      __ nop();
+    }
     lazy_deopt_pc_offset_ = assembler()->CodeSize();
     __ Branch(*StubCode::DeoptimizeLazy_entry());
   }