[clang] [clang-tools-extra] [clang][DependencyScanning] Separate clangDependencyScanning and DependencyScanningTool (NFC) (PR #169962)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64le-linux-multistage` running on `ppc64le-clang-multistage-test` while building `clang-tools-extra,clang` at step 11 "ninja check 2".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/76/builds/13515

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 11 (ninja check 2) failure: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
...
PASS: Clang :: Driver/arm-cortex-cpus-1.c (104407 of 104417)
PASS: Clang :: Preprocessor/arm-target-features.c (104408 of 104417)
PASS: Clang :: Preprocessor/aarch64-target-features.c (104409 of 104417)
PASS: SanitizerCommon-tsan-powerpc64le-Linux :: Linux/signal_segv_handler.cpp (104410 of 104417)
PASS: SanitizerCommon-ubsan-powerpc64le-Linux :: Linux/signal_segv_handler.cpp (104411 of 104417)
PASS: SanitizerCommon-lsan-powerpc64le-Linux :: Linux/signal_segv_handler.cpp (104412 of 104417)
PASS: Clang :: OpenMP/target_update_codegen.cpp (104413 of 104417)
PASS: SanitizerCommon-asan-powerpc64le-Linux :: Linux/signal_segv_handler.cpp (104414 of 104417)
PASS: SanitizerCommon-msan-powerpc64le-Linux :: Linux/signal_segv_handler.cpp (104415 of 104417)
PASS: Clang :: Preprocessor/riscv-target-features.c (104416 of 104417)
command timed out: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=6052.776671

```

</details>

https://github.com/llvm/llvm-project/pull/169962