[llvm] Add unit tests for size returning new funcs in the MemProf use pass. (PR #105473)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-nvptx-nvidia-ubuntu` running on `as-builder-7` while building `llvm` at step 6 "test-build-unified-tree-check-llvm".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/180/builds/3941

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

```
Step 6 (test-build-unified-tree-check-llvm) failure: test (failure)
...
1.189 [3/6/652] Linking CXX executable unittests/Support/SupportTests
1.205 [3/5/653] Linking CXX executable unittests/ADT/ADTTests
10.207 [3/4/654] Building CXX object unittests/ProfileData/CMakeFiles/ProfileDataTests.dir/CoverageMappingTest.cpp.o
/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/unittests/ProfileData/CoverageMappingTest.cpp: In member function ‘virtual void {anonymous}::CoverageMappingTest_TVIdxBuilder_Test::TestBody()’:
/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/unittests/ProfileData/CoverageMappingTest.cpp:1116:10: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wdangling-else]
 1116 |       if (Node.NextIDs[C] < 0)
      |          ^
11.574 [3/3/655] Building CXX object unittests/ProfileData/CMakeFiles/ProfileDataTests.dir/MemProfTest.cpp.o
12.284 [3/2/656] Building CXX object unittests/Transforms/Instrumentation/CMakeFiles/InstrumentationTests.dir/MemProfilerTest.cpp.o
12.393 [2/2/657] Linking CXX executable unittests/Transforms/Instrumentation/InstrumentationTests
FAILED: unittests/Transforms/Instrumentation/InstrumentationTests 
: && /usr/bin/c++ -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -fuse-ld=gold     -Wl,--gc-sections unittests/Transforms/Instrumentation/CMakeFiles/InstrumentationTests.dir/PGOInstrumentationTest.cpp.o unittests/Transforms/Instrumentation/CMakeFiles/InstrumentationTests.dir/MemProfilerTest.cpp.o -o unittests/Transforms/Instrumentation/InstrumentationTests  -Wl,-rpath,/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/build/lib  lib/libLLVMPasses.so.20.0git  lib/libllvm_gtest_main.so.20.0git  lib/libLLVMTestingSupport.so.20.0git  lib/libLLVMInstrumentation.so.20.0git  lib/libLLVMAnalysis.so.20.0git  lib/libLLVMAsmParser.so.20.0git  lib/libLLVMCore.so.20.0git  lib/libllvm_gtest.so.20.0git  lib/libLLVMSupport.so.20.0git  -Wl,-rpath-link,/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/build/lib && :
unittests/Transforms/Instrumentation/CMakeFiles/InstrumentationTests.dir/MemProfilerTest.cpp.o:MemProfilerTest.cpp:function llvm::memprof::(anonymous namespace)::MockMemProfReader::~MockMemProfReader(): error: undefined reference to 'vtable for llvm::IndexedMemProfReader'
/usr/bin/ld.gold: the vtable symbol may be undefined because the class is missing its key function
unittests/Transforms/Instrumentation/CMakeFiles/InstrumentationTests.dir/MemProfilerTest.cpp.o:MemProfilerTest.cpp:function llvm::memprof::(anonymous namespace)::MockMemProfReader::~MockMemProfReader(): error: undefined reference to 'vtable for llvm::IndexedMemProfReader'
/usr/bin/ld.gold: the vtable symbol may be undefined because the class is missing its key function
unittests/Transforms/Instrumentation/CMakeFiles/InstrumentationTests.dir/MemProfilerTest.cpp.o:MemProfilerTest.cpp:function llvm::IndexedMemProfReader::~IndexedMemProfReader(): error: undefined reference to 'vtable for llvm::IndexedMemProfReader'
/usr/bin/ld.gold: the vtable symbol may be undefined because the class is missing its key function
unittests/Transforms/Instrumentation/CMakeFiles/InstrumentationTests.dir/MemProfilerTest.cpp.o:MemProfilerTest.cpp:function llvm::memprof::(anonymous namespace)::MemProfilerTest_AnnotatesCall_Test::TestBody(): error: undefined reference to 'llvm::memprof::getHotColdSchema()'
collect2: error: ld returned 1 exit status
18.578 [2/1/658] Building CXX object unittests/ProfileData/CMakeFiles/ProfileDataTests.dir/InstrProfTest.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/105473