[llvm] [SandboxIR][NFC] Move Region from SandboxVectorizer to SandboxIR. (PR #110173)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-x86_64-debian-fast` running on `gribozavr4` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/56/builds/8499

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
...
11.118 [2/39/1137] Linking CXX executable unittests/tools/llvm-profdata/LLVMProfdataTests
11.191 [2/38/1138] Linking CXX executable unittests/Transforms/Vectorize/SandboxVectorizer/SandboxVectorizerTests
11.258 [2/37/1139] Linking CXX executable unittests/IR/IRTests
11.472 [2/36/1140] Linking CXX executable tools/clang/unittests/Driver/ClangDriverTests
11.484 [2/35/1141] Linking CXX executable unittests/Transforms/Vectorize/VectorizeTests
11.550 [2/34/1142] Linking CXX executable unittests/MC/AMDGPU/AMDGPUMCTests
11.669 [2/33/1143] Linking CXX executable unittests/Passes/PassBuilderBindings/PassesBindingsTests
11.671 [2/32/1144] Linking CXX executable unittests/ExecutionEngine/Orc/OrcJITTests
11.685 [2/31/1145] Linking CXX executable unittests/Transforms/IPO/IPOTests
11.715 [2/30/1146] Building CXX object unittests/SandboxIR/CMakeFiles/SandboxIRTests.dir/RegionTest.cpp.o
FAILED: unittests/SandboxIR/CMakeFiles/SandboxIRTests.dir/RegionTest.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes /usr/bin/ccache /usr/bin/clang++ -DGTEST_HAS_RTTI=0 -DLLVM_BUILD_STATIC -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/b/1/clang-x86_64-debian-fast/llvm.obj/unittests/SandboxIR -I/b/1/clang-x86_64-debian-fast/llvm.src/llvm/unittests/SandboxIR -I/b/1/clang-x86_64-debian-fast/llvm.obj/include -I/b/1/clang-x86_64-debian-fast/llvm.src/llvm/include -I/b/1/clang-x86_64-debian-fast/llvm.src/third-party/unittest/googletest/include -I/b/1/clang-x86_64-debian-fast/llvm.src/third-party/unittest/googlemock/include -std=c++11 -Wdocumentation -Wno-documentation-deprecated-sync -fPIC -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -Wno-variadic-macros -Wno-gnu-zero-variadic-macro-arguments -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -Wno-suggest-override -std=c++17 -MD -MT unittests/SandboxIR/CMakeFiles/SandboxIRTests.dir/RegionTest.cpp.o -MF unittests/SandboxIR/CMakeFiles/SandboxIRTests.dir/RegionTest.cpp.o.d -o unittests/SandboxIR/CMakeFiles/SandboxIRTests.dir/RegionTest.cpp.o -c /b/1/clang-x86_64-debian-fast/llvm.src/llvm/unittests/SandboxIR/RegionTest.cpp
/b/1/clang-x86_64-debian-fast/llvm.src/llvm/unittests/SandboxIR/RegionTest.cpp:9:10: fatal error: 'llvm/Transforms/Vectorize/SandboxVectorizer/Region.h' file not found
#include "llvm/Transforms/Vectorize/SandboxVectorizer/Region.h"
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
12.097 [2/29/1147] Linking CXX executable unittests/Passes/Plugins/PluginsTests
12.101 [2/28/1148] Linking CXX executable unittests/tools/llvm-cfi-verify/CFIVerifyTests
12.141 [2/27/1149] Linking CXX executable unittests/Transforms/Coroutines/CoroTests
12.206 [2/26/1150] Linking CXX executable tools/clang/unittests/CodeGen/ClangCodeGenTests
12.344 [2/25/1151] Linking CXX executable unittests/Target/VE/VETests
12.378 [2/24/1152] Linking CXX executable unittests/Target/LoongArch/LoongArchTests
12.383 [2/23/1153] Linking CXX executable unittests/Target/WebAssembly/WebAssemblyTests
12.403 [2/22/1154] Linking CXX executable unittests/Target/ARM/ARMTests
12.421 [2/21/1155] Linking CXX executable unittests/Target/RISCV/RISCVTests
12.421 [2/20/1156] Linking CXX executable unittests/Transforms/Instrumentation/InstrumentationTests
12.426 [2/19/1157] Linking CXX executable unittests/Target/PowerPC/PowerPCTests
12.428 [2/18/1158] Linking CXX executable unittests/Transforms/Utils/UtilsTests
12.501 [2/17/1159] Linking CXX executable unittests/CodeGen/GlobalISel/GlobalISelTests
12.520 [2/16/1160] Linking CXX executable unittests/Target/AArch64/AArch64Tests
12.611 [2/15/1161] Linking CXX executable unittests/tools/llvm-mca/LLVMMCATests
12.831 [2/14/1162] Linking CXX executable unittests/MI/MITests
12.883 [2/13/1163] Linking CXX executable unittests/CodeGen/CodeGenTests
12.962 [2/12/1164] Linking CXX executable unittests/Transforms/Scalar/ScalarTests
12.971 [2/11/1165] Linking CXX executable unittests/DebugInfo/DWARF/DebugInfoDWARFTests
13.082 [2/10/1166] Linking CXX executable unittests/Target/X86/X86Tests
13.135 [2/9/1167] Linking CXX executable tools/clang/unittests/Frontend/FrontendTests
13.188 [2/8/1168] Linking CXX executable unittests/Target/AMDGPU/AMDGPUTests
13.214 [2/7/1169] Linking CXX executable unittests/tools/llvm-exegesis/LLVMExegesisTests
13.287 [2/6/1170] Linking CXX executable unittests/MIR/MIRTests
13.352 [2/5/1171] Linking CXX executable tools/clang/unittests/Interpreter/ExceptionTests/ClangReplInterpreterExceptionTests
14.085 [2/4/1172] Linking CXX executable unittests/Target/TargetMachineCTests
15.532 [2/3/1173] Linking CXX executable tools/clang/unittests/Tooling/ToolingTests
16.502 [2/2/1174] Linking CXX executable tools/clang/unittests/Interpreter/ClangReplInterpreterTests
16.601 [2/1/1175] Linking CXX executable tools/clang/tools/extra/clangd/unittests/ClangdTests
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/110173