hctstart.cmd and hctbuild.cmd now support ARM64 builds.
Note that building ARM64 build on x86/x64 machine needs a location
of x86/x64 version of TableGen tools (clang-tblgen and llvm-tblgen).
Before starting ARM64 build set the BUILD_TBLGEN_PATH to point to
the TableGen binaries or use the -tblgen option on hctbuild.cmd.
Also had to rearrange control flow around the cmake --build call
in hctbuild.cmd due to a flaky batch behavior around brackets.
Helena Kotas
Marcelo Lopez Ruiz
Lei Zhang