[BPF] Triple::isBPF() utility method

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

Differential Revision: https://reviews.llvm.org/D140969

Author: eddyz87

llvm/include/llvm/TargetParser/Triple.h

@@ -939,6 +939,11 @@ class Triple {
     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() ||