[LLDB] [PECOFF] Use a "pc" vendor name in aarch64 triples

This matches all other architectures listed in the same file.

This fixes debugging aarch64 executables with lldb-server, which
otherwise fails, with log messages like these:

Target::SetArchitecture changing architecture to aarch64 (aarch64-pc-windows-msvc)
Target::SetArchitecture Trying to select executable file architecture aarch64 (aarch64-pc-windows-msvc)

ArchSpec::SetArchitecture sets the vendor to llvm::Triple::PC
for any coff/win32 combination, and if this doesn't match the triple
set by the PECOFF module, things doesn't seem to work with when
using lldb-server.

Differential Revision: https://reviews.llvm.org/D68939

llvm-svn: 374867

lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp

@@ -200,7 +200,7 @@ size_t ObjectFilePECOFF::GetModuleSpecifications(
     specs.Append(module_spec);
     break;
   case MachineArm64:
-    spec.SetTriple("aarch64-unknown-windows");
+    spec.SetTriple("aarch64-pc-windows");
     specs.Append(module_spec);
     break;
   default:

lldb/test/Shell/ObjectFile/PECOFF/basic-info-arm64.yaml

@@ -2,7 +2,7 @@
 # RUN: lldb-test object-file %t | FileCheck %s
 
 # CHECK: Plugin name: pe-coff
-# CHECK: Architecture: aarch64-unknown-windows-msvc
+# CHECK: Architecture: aarch64-pc-windows-msvc
 # CHECK: UUID: 
 # CHECK: Executable: true
 # CHECK: Stripped: false