[Test] Underscored deleter_delete_if_dead.

Use underscores rather than hyphens so that text editors understand the
name as a single word.

Author: nate-chandler

lib/SILOptimizer/Utils/InstructionDeleter.cpp

@@ -335,7 +335,7 @@ namespace swift::test {
 // Dumps:
 // - the function
 static FunctionTest DeleterDeleteIfDeadTest(
-    "deleter-delete-if-dead", [](auto &function, auto &arguments, auto &test) {
+    "deleter_delete_if_dead", [](auto &function, auto &arguments, auto &test) {
       auto *inst = arguments.takeInstruction();
       InstructionDeleter deleter;
       llvm::outs() << "Deleting-if-dead " << *inst;

test/SILOptimizer/instruction_deleter.sil

@@ -27,7 +27,7 @@ sil [ossa] @dontDeleteDeadMoveOnlyValue : $() -> () {
   %get = function_ref @getMOS : $@convention(thin) () -> (@owned MOS)
   %barrier = function_ref @barrier : $@convention(thin) () -> ()
   %mos = apply %get() : $@convention(thin) () -> (@owned MOS)
-  specify_test "deleter-delete-if-dead @instruction"
+  specify_test "deleter_delete_if_dead @instruction"
   %mov = move_value %mos : $MOS
   apply %barrier() : $@convention(thin) () -> ()
   destroy_value %mov : $MOS
@@ -50,7 +50,7 @@ sil [ossa] @doDeleteLoadTake : $() -> () {
   %stack = alloc_stack $C
   %get = function_ref @get : $@convention(thin) <T> () -> (@out T)
   apply %get<C>(%stack) : $@convention(thin) <T> () -> (@out T)
-  specify_test "deleter-delete-if-dead @instruction"
+  specify_test "deleter_delete_if_dead @instruction"
   %c = load [take] %stack : $*C
   destroy_value %c : $C
   dealloc_stack %stack : $*C