Fix paltests build

[am11]

https://dev.azure.com/dnceng-public/public/_build/results?buildId=708804&view=logs&jobId=a3b522d2-1fcb-58aa-d1da-345566122d64&j=a3b522d2-1fcb-58aa-d1da-345566122d64&t=28177cd9-7046-57c0-17a4-2d126beee140

/__w/1/s/build.sh -ci -arch arm64 -os linux -cross -s clr.paltests+clr.paltestlist      
...
  [ 70%] Building CXX object pal/tests/palsuite/CMakeFiles/paltests.dir/file_io/ReadFile/test3/ReadFile.cpp.o
  /__w/1/s/src/coreclr/pal/tests/palsuite/file_io/ReadFile/test2/ReadFile.cpp:132:29: error: non-constant-expression cannot be narrowed from type 'size_t' (aka 'unsigned long') to 'DWORD' (aka 'unsigned int') in initializer list [-Wc++11-narrowing]
    132 |                             strlen(szStringTest),
        |                             ^~~~~~~~~~~~~~~~~~~~
  /__w/1/s/src/coreclr/pal/tests/palsuite/file_io/ReadFile/test2/ReadFile.cpp:132:29: note: insert an explicit cast to silence this issue
    132 |                             strlen(szStringTest),
        |                             ^~~~~~~~~~~~~~~~~~~~
        |                             static_cast<DWORD>( )
  /__w/1/s/src/coreclr/pal/tests/palsuite/file_io/ReadFile/test2/ReadFile.cpp:133:29: error: non-constant-expression cannot be narrowed from type 'long' to 'DWORD' (aka 'unsigned int') in initializer list [-Wc++11-narrowing]
    133 |                             pageSize
        |                             ^~~~~~~~
  /__w/1/s/src/coreclr/pal/tests/palsuite/file_io/ReadFile/test2/ReadFile.cpp:133:29: note: insert an explicit cast to silence this issue
    133 |                             pageSize
        |                             ^~~~~~~~
        |                             static_cast<DWORD>( )
  [ 70%] Building CXX object pal/tests/palsuite/CMakeFiles/paltests.dir/file_io/ReadFile/test4/readfile.cpp.o
  2 errors generated.

[jkotas]

Should this implicit size_t -> int cast be made explicit as well? It is interesting that the compiler is not complaining about this strlen("constant string"), but it is complaining about the other strlen("constant string").

[am11]

Declaring it as DWORD also works without the explicit cast.

[jkotas]

I would not depend on it. In general, compilers complain about any implicit narrowing these days.

[jkotas]

Thanks