Add a triple to test/ExecutionEngine/MCJIT/cet-code-model-lager.ll

It was failing in 32-bit Windows builds with:

  $ ":" "RUN: at line 1"
  $ "c:\src\llvm_package_944db8a4\build32_stage0\bin\lli.exe" "-mtriple=i686-pc-windows-msvc-elf" "-code-model=large" "C:\src\llvm_package_944db8a4\llvm-project\llvm\test\ExecutionEngine\MCJIT\cet-code-model-lager.ll"
  # command stderr:
  Assertion failed: Is64Bit && "Large code model is only legal in 64-bit mode.", file C:\src\llvm_package_944db8a4\llvm-project\llvm\lib\Target\X86\X86ISelLowering.cpp, line 4212

Let's see if this helps.