Add ARM IntelliSenseModes

[michelleangela]

Add the following ARM IntelliSenseModes

IntelliSenseMode	description
clang-arm	Targets ARM 32-bit architecture and simulates compiling with Clang
clang-arm64	Targets ARM 64-bit architecture and simulates compiling with Clang
gcc-arm	Targets ARM 32-bit architecture and simulates compiling with Gcc
gcc-arm64	Targets ARM 64-bit architecture and simulates compiling with Gcc
msvc-arm	Targets ARM 32-bit architecture and simulates compiling with msvc (Microsoft C++ compiler)
msvc-arm64	Targets ARM 64-bit architecture and simulates compiling with msvc (Microsoft C++ compiler)

Feature request: #4271

[aelray]

I'm using 0.28.0-insiders3 and it doesn't work with ARMClang. I get incorrect code highlighting until I add some defines, which usually the compiler would provide. Also includes are handled wrongly, it still tries to resolve stdint.h from the c stdlib instead of from the ARMClang toolchain directory.

[michelleangela]

@aelray, could you create a new issue and provide your c_cpp_properties.json and the C/C++ language server logging when opening the project? The defines should have been queried from the compiler. Perhaps the extension failed to query the compiler so it could not get the defines and relative paths of the library header files.