clang/module.modulemap: Split out Clang_ToolingCore from Clang_Tooling.

It cuts clangFormat's dependencies out of;

  Clang_Analysis
  Clang_C
  Clang_Diagnostics
  Clang_Driver
  Clang_Frontend
  Clang_Sema
  Clang_Serialization
  Clang_StaticAnalyzer_Core
  Clang_Tooling -> Clang_ToolingCore

Now, the module Clang_Format depends on;

  Clang_AST
  Clang_Basic
  Clang_ToolingCore

llvm-svn: 308832