Port irregexp bytecode compiler and interpreter from V8 r24065.

runtime/vm/intrinsifier_arm64.cc

Index: runtime/vm/intrinsifier_arm64.cc
diff --git a/runtime/vm/intrinsifier_arm64.cc b/runtime/vm/intrinsifier_arm64.cc
index 92b65799dc43bc2a4d676bdf467367921b20217f..dd46bcc6bd2e7023a052810133e9ffba4669bb13 100644
--- a/runtime/vm/intrinsifier_arm64.cc
+++ b/runtime/vm/intrinsifier_arm64.cc
@@ -17,6 +17,8 @@
 
 namespace dart {
 
+DECLARE_FLAG(bool, interpret_irregexp);
+
 // When entering intrinsics code:
 // R5: IC Data
 // R4: Arguments descriptor
@@ -2067,6 +2069,8 @@ void Intrinsifier::TwoByteString_equality(Assembler* assembler) {
 
 
 void Intrinsifier::JSRegExp_ExecuteMatch(Assembler* assembler) {
+  if (FLAG_interpret_irregexp) return;
+
   static const intptr_t kRegExpParamOffset = 2 * kWordSize;
   static const intptr_t kStringParamOffset = 1 * kWordSize;
   // start_index smi is located at offset 0.