[NFC] Eliminate use of lookupLLVMIntrinsicByName in Coroutines

Eliminate use of `lookupLLVMIntrinsicByName` from Coroutines in
preparation of changing it to support a different form of intrinsic
name table generated by intrinsic emitter.

Also eliminate call to `isCoroutineIntrinsicName` from
`declaresAnyIntrinsic` as the list of names traversed is the same
list which `isCoroutineIntrinsicName` checks.

Author: jurahul

llvm/lib/Transforms/Coroutines/Coroutines.cpp

@@ -100,8 +100,7 @@ static const char *const CoroIntrinsics[] = {
 
 #ifndef NDEBUG
 static bool isCoroutineIntrinsicName(StringRef Name) {
-  return Intrinsic::lookupLLVMIntrinsicByName(CoroIntrinsics, Name, "coro") !=
-         -1;
+  return llvm::binary_search(CoroIntrinsics, Name);
 }
 #endif
 
@@ -111,7 +110,6 @@ bool coro::isSuspendBlock(BasicBlock *BB) {
 
 bool coro::declaresAnyIntrinsic(const Module &M) {
   for (StringRef Name : CoroIntrinsics) {
-    assert(isCoroutineIntrinsicName(Name) && "not a coroutine intrinsic");
     if (M.getNamedValue(Name))
       return true;
   }