Use JitFuncInfoLogFile to check if SIMD intrinsics are recognized.

Use JitFuncInfoLogFile to check if SIMD intrinsics are recognized.

Although COMPlus_JitFuncInfoLogFile was enabled as a "RETAIL" variable, it
was only opening the file (and not writing to it) in non-DEBUG.
In order to use it, we need to also enable eeGetMethodFullName in release,
which in turn requires type names.
Also, _wfsopen() is not supported in the PAL layer.
However, it appears to work fine without the sharing option, on both Windows
and Linux.
Add a utility class to use the log file to check whether a method has been compiled.
Use it to test that the SIMD intrinsics are not compiled when they are enabled.
Add dir.props to the SIMD test directory to set the COMPlus_JitFuncInfoLogFile
environment variable, and to delete the log file before each test.

Fix dotnet/coreclr#2554

Commit migrated from https://github.com/dotnet/coreclr/commit/41057591615c9ed32567de5936bf72de29c5118c