[X86] Print 'l' section flag for SHF_X86_64_LARGE (#70380)

When directly compiling to an object file we properly set the section
flag, but not when emitting assembly.

Author: aeubanks

llvm/lib/MC/MCSectionELF.cpp

@@ -123,6 +123,9 @@ void MCSectionELF::printSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
   } else if (Arch == Triple::hexagon) {
     if (Flags & ELF::SHF_HEX_GPREL)
       OS << 's';
+  } else if (Arch == Triple::x86_64) {
+    if (Flags & ELF::SHF_X86_64_LARGE)
+      OS << 'l';
   }
 
   OS << '"';

llvm/test/MC/ELF/section.s

@@ -269,6 +269,8 @@ bar:
 // CHECK-NEXT:     ]
 
 .section .large,"l"
+// ASM: .section .large,"l"
+
 // CHECK:        Section {
 // CHECK:          Name: .large
 // CHECK-NEXT:     Type: SHT_PROGBITS