Enable optimization of functions with generic switches.

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 473f548500b170793864daa0ab227446d532b900..3d6107552f1041d7ad408026afdc077bcd88013b 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -986,6 +986,15 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
     CallIC(ic, RelocInfo::CODE_TARGET, clause->CompareId());
     patch_site.EmitPatchInfo();
 
+    Label skip;
+    __ jmp(&skip, Label::kNear);
+    PrepareForBailout(clause, TOS_REG);
+    __ CompareRoot(rax, Heap::kTrueValueRootIndex);
+    __ j(not_equal, &next_test);
+    __ Drop(1);
+    __ jmp(clause->body_target());
+    __ bind(&skip);
+
     __ testq(rax, rax);
     __ j(not_equal, &next_test);
     __ Drop(1);  // Switch value is no longer needed.