[clang][deps] Substitute clang-scan-deps executable in lit tests

The lit tests for `clang-scan-deps` invoke the tool without going through the substitution system. While the test runner correctly picks up the `clang-scan-deps` binary from the build directory, it doesn't print its absolute path. When copying the invocations when reproducing test failures, this can result in `command not found: clang-scan-deps` errors or worse yet: pick up the system `clang-scan-deps`. This patch adds new local `%clang-scan-deps` substitution.

Reviewed By: lxfind, dblaikie

Differential Revision: https://reviews.llvm.org/D107155

Author: jansvoboda11

clang/test/lit.cfg.py

@@ -64,7 +64,7 @@
 
 tools = [
     'apinotes-test', 'c-index-test', 'clang-diff', 'clang-format', 'clang-repl',
-    'clang-tblgen', 'opt', 'llvm-ifs', 'yaml2obj',
+    'clang-tblgen', 'clang-scan-deps', 'opt', 'llvm-ifs', 'yaml2obj',
     ToolSubst('%clang_extdef_map', command=FindTool(
         'clang-extdef-mapping'), unresolved='ignore'),
 ]