Add the dummy implementation for turbofan unsupported port.

This is introduced by acd9c46ca7 (r26691).

BUG=

Review URL: https://codereview.chromium.org/965673002

Cr-Commit-Position: refs/heads/master@{#26901}

src/compiler/instruction-selector.cc

@@ -1212,6 +1212,14 @@ void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
 }
 
 
+void InstructionSelector::VisitSwitch(Node* node, BasicBlock* default_branch,
+                                      BasicBlock** case_branches,
+                                      int32_t* case_values, size_t case_count,
+                                      int32_t min_value, int32_t max_value) {
+  UNIMPLEMENTED();
+}
+
+
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {