need 'use_siso=true' for clang_need_input_root_absoute_path

Siso can set InputRootAbsolutePath appropriately, but
there is no easy way to set it in ninja+reclient

Bug: 344607450
Change-Id: Ifef3947be31c1c1036d53eded6891f9eb20327c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5613112


Auto-Submit: Fumitoshi Ukai <ukai@google.com>
Reviewed-by: Junji Watanabe <jwata@google.com>
Commit-Queue: Fumitoshi Ukai <ukai@google.com>
Reviewed-by: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1312622}