[FuncSpec][NFC] Fix test for literal constant specialisation

[chill]

Summary

[FuncSpec][NFC] Fix test for literal constant specialisation

The specialised function names depend in the order of specialisation,
which is the order as obtained by for (Function &F : M) { ... and
if this order is reversed tests that mention cloned function names
may break.

This patch fixes a failure triggered by -DLLVM_REVERSE_ITERATION:ON by
making the test not depend on specific cloned function names.

[ChuanqiXu]

Generally we'd revert the D135893, otherwise it'll exist without a test. Reverting is common in LLVM and it doesn't mean a lot.

llvm/test/Transforms/FunctionSpecialization/literal-const.ll

 ; RUN: opt -S --passes=function-specialization \
 ; RUN:        -force-function-specialization < %s | FileCheck %s -check-prefix CHECK-NOLIT
 ; RUN: opt -S --passes=function-specialization \
 ; RUN:        -function-specialization-for-literal-constant \
 ; RUN:        -force-function-specialization < %s | FileCheck %s -check-prefix CHECK-LIT
 
+; UNSUPPORTED: all
+
 define dso_local i32 @f0(i32 noundef %x) {
 entry:
   %call = tail call fastcc i32 @neg(i32 noundef %x, i1 noundef zeroext false)
   ret i32 %call
 }
 
 define internal fastcc i32 @neg(i32 noundef %x, i1 noundef zeroext %b) {
 entry: