Use internal linkage for __NoopCoro_ResumeDestroy (llvm#159407)

`__NoopCoro_ResumeDestroy` currently has private linkage, which causes
[issues for
Arm64EC](llvm#158341). The
Arm64EC lowering is trying to mangle and add thunks for
`__NoopCoro_ResumeDestroy`, since it sees that it's address is taken
(and, therefore, might be called from x64 code via a function pointer).
MSVC's linker requires that the function be placed in COMDAT (`LNK1361:
non COMDAT symbol '.L#__NoopCoro_ResumeDestroy' in hybrid binary`) which
trips an assert in the verifier (`comdat global value has private
linkage`) and the subsequent linking step fails since the private symbol
isn't in the symbol table.

Since there is no reason to use private linkage for
`__NoopCoro_ResumeDestroy` and other coro related functions have also
been [switched to internal linkage to improve
debugging](llvm#151224), this
change switches to using internal linkage.

Fixes llvm#158341

Author: dpaoliello

llvm/lib/Transforms/Coroutines/CoroEarly.cpp

@@ -132,7 +132,7 @@ void Lowerer::lowerCoroNoop(IntrinsicInst *II) {
 
     // Create a Noop function that does nothing.
     Function *NoopFn = Function::createWithDefaultAttr(
-        FnTy, GlobalValue::LinkageTypes::PrivateLinkage,
+        FnTy, GlobalValue::LinkageTypes::InternalLinkage,
         M.getDataLayout().getProgramAddressSpace(), "__NoopCoro_ResumeDestroy",
         &M);
     NoopFn->setCallingConv(CallingConv::Fast);

llvm/test/Transforms/Coroutines/coro-noop-pacbti.ll

@@ -1,7 +1,7 @@
 
 ; RUN: opt < %s -S -passes=coro-early | FileCheck %s
 
-; CHECK:      define private fastcc void @__NoopCoro_ResumeDestroy(ptr %0) #1 {
+; CHECK:      define internal fastcc void @__NoopCoro_ResumeDestroy(ptr %0) #1 {
 ; CHECK-NEXT: entry:
 ; CHECK-NEXT:   ret void
 ; CHECK-NEXT: }

llvm/test/Transforms/Coroutines/coro-noop.ll

@@ -26,7 +26,7 @@ declare ptr @llvm.coro.noop()
 !4 = !{i32 2, !"Debug Info Version", i32 3}
 
 
-; CHECK: define private fastcc void @__NoopCoro_ResumeDestroy(ptr %0) !dbg ![[RESUME:[0-9]+]] {
+; CHECK: define internal fastcc void @__NoopCoro_ResumeDestroy(ptr %0) !dbg ![[RESUME:[0-9]+]] {
 ; CHECK-NEXT: entry
 ; CHECK-NEXT:    ret void