Update {virtual,override} to follow C++11 style in courgette.

The Google style guide states that only one of {virtual,override,final} should be used for each declaration, since override implies virtual and final implies both virtual and override.

This patch was manually generated using a regex and a text editor.

BUG=417463

Review URL: https://codereview.chromium.org/1052683004

Cr-Commit-Position: refs/heads/master@{#326831}

courgette/disassembler_elf_32_x86.h

@@ -21,17 +21,17 @@ class DisassemblerElf32X86 : public DisassemblerElf32 {
     explicit TypedRVAX86(RVA rva) : TypedRVA(rva) {
     }
 
-    virtual CheckBool ComputeRelativeTarget(const uint8* op_pointer) override {
+    CheckBool ComputeRelativeTarget(const uint8* op_pointer) override {
       set_relative_target(Read32LittleEndian(op_pointer) + 4);
       return true;
     }
 
-    virtual CheckBool EmitInstruction(AssemblyProgram* program,
-                                       RVA target_rva) override {
+    CheckBool EmitInstruction(AssemblyProgram* program,
+                              RVA target_rva) override {
       return program->EmitRel32(program->FindOrMakeRel32Label(target_rva));
     }
 
-    virtual uint16 op_size() const override { return 4; }
+    uint16 op_size() const override { return 4; }
   };
 
   explicit DisassemblerElf32X86(const void* start, size_t length);