[llvm] TableGen: Split RuntimeLibcallsEmitter into separate utility header (PR #166583)

[Rahul Joshi via llvm-commits]

================
@@ -0,0 +1,189 @@
+//===--- RuntimeLibcalls.h --------------------------------------*- C++ -*-===//
----------------
jurahul wrote:

nit: filename not needed per latest CS

https://github.com/llvm/llvm-project/pull/166583