[BPF] Triple::isBPF() utility method

[eddyz87]

Summary

Adds a utility method llvm::Triple::isBPF() aggregating Triple::bpfel
and Triple::bpfeb architectures. Similar to other predicates in this class.

[eddyz87]

Just a rebase.

llvm/include/llvm/TargetParser/Triple.h

public:
   }
 
   /// Tests whether the target is X32.
   bool isX32() const {
     EnvironmentType Env = getEnvironment();
     return Env == Triple::GNUX32 || Env == Triple::MuslX32;
   }
 
+  /// Tests whether the target is eBPF.
+  bool isBPF() const {
+    return getArch() == Triple::bpfel || getArch() == Triple::bpfeb;
+  }
+
   /// Tests whether the target supports comdat
   bool supportsCOMDAT() const {
     return !(isOSBinFormatMachO() || isOSBinFormatXCOFF() ||
              isOSBinFormatDXContainer());
   }
 
   /// Tests whether the target uses emulated TLS as default.
   bool hasDefaultEmulatedTLS() const {