[lldb] use the default instruction flavour if none is provided

this is already done in the other overloaded function `SBTarget::ReadInstructions::(SBAddress, SBAddress, const char *)`

It completes it to be more in line wither other `ReadInstruction/GetInstructions` api

Author: da-viper

lldb/source/API/SBTarget.cpp

@@ -2039,7 +2039,17 @@ lldb::SBInstructionList SBTarget::ReadInstructions(lldb::SBAddress base_addr,
       const size_t bytes_read =
           target_sp->ReadMemory(*addr_ptr, data.GetBytes(), data.GetByteSize(),
                                 error, force_live_memory, &load_addr);
+
       const bool data_from_file = load_addr == LLDB_INVALID_ADDRESS;
+      if (!flavor_string || flavor_string[0] == '\0') {
+        // FIXME - we don't have the mechanism in place to do per-architecture
+        // settings.  But since we know that for now we only support flavors on
+        // x86 & x86_64,
+        const llvm::Triple::ArchType arch =
+            target_sp->GetArchitecture().GetTriple().getArch();
+        if (arch == llvm::Triple::x86 || arch == llvm::Triple::x86_64)
+          flavor_string = target_sp->GetDisassemblyFlavor();
+      }
       sb_instructions.SetDisassembler(Disassembler::DisassembleBytes(
           target_sp->GetArchitecture(), nullptr, flavor_string,
           target_sp->GetDisassemblyCPU(), target_sp->GetDisassemblyFeatures(),
@@ -2098,7 +2108,16 @@ SBTarget::GetInstructionsWithFlavor(lldb::SBAddress base_addr,
     if (base_addr.get())
       addr = *base_addr.get();
 
-    const bool data_from_file = true;
+    constexpr bool data_from_file = true;
+    if (!flavor_string || flavor_string[0] == '\0') {
+      // FIXME - we don't have the mechanism in place to do per-architecture
+      // settings.  But since we know that for now we only support flavors on
+      // x86 & x86_64,
+      const llvm::Triple::ArchType arch =
+          target_sp->GetArchitecture().GetTriple().getArch();
+      if (arch == llvm::Triple::x86 || arch == llvm::Triple::x86_64)
+        flavor_string = target_sp->GetDisassemblyFlavor();
+    }
 
     sb_instructions.SetDisassembler(Disassembler::DisassembleBytes(
         target_sp->GetArchitecture(), nullptr, flavor_string,