[sanitizer] [msan] Unify aarch64 mapping

This patch unify the 39-bit and 42-bit mapping for aarch64 to use only
one instrumentation algorithm.  This removes compiler flag 
SANITIZER_AARCH64_VMA requirement for MSAN on aarch64.

The mapping to use now is for 39 and 42-bits:

    0x00000000000ULL-0x01000000000ULL  MappingDesc::INVALID
    0x01000000000ULL-0x02000000000ULL  MappingDesc::SHADOW
    0x02000000000ULL-0x03000000000ULL  MappingDesc::ORIGIN
    0x03000000000ULL-0x04000000000ULL  MappingDesc::SHADOW
    0x04000000000ULL-0x05000000000ULL  MappingDesc::ORIGIN
    0x05000000000ULL-0x06000000000ULL  MappingDesc::APP
    0x06000000000ULL-0x07000000000ULL  MappingDesc::INVALID
    0x07000000000ULL-0x08000000000ULL  MappingDesc::APP

And only for 42-bits:

    0x08000000000ULL-0x09000000000ULL  MappingDesc::INVALID
    0x09000000000ULL-0x0A000000000ULL  MappingDesc::SHADOW
    0x0A000000000ULL-0x0B000000000ULL  MappingDesc::ORIGIN
    0x0B000000000ULL-0x0F000000000ULL  MappingDesc::INVALID
    0x0F000000000ULL-0x10000000000ULL  MappingDesc::APP
    0x10000000000ULL-0x11000000000ULL  MappingDesc::INVALID
    0x11000000000ULL-0x12000000000ULL  MappingDesc::APP
    0x12000000000ULL-0x17000000000ULL  MappingDesc::INVALID
    0x17000000000ULL-0x18000000000ULL  MappingDesc::SHADOW
    0x18000000000ULL-0x19000000000ULL  MappingDesc::ORIGIN
    0x19000000000ULL-0x20000000000ULL  MappingDesc::INVALID
    0x20000000000ULL-0x21000000000ULL  MappingDesc::APP
    0x21000000000ULL-0x26000000000ULL  MappingDesc::INVALID
    0x26000000000ULL-0x27000000000ULL  MappingDesc::SHADOW
    0x27000000000ULL-0x28000000000ULL  MappingDesc::ORIGIN
    0x28000000000ULL-0x29000000000ULL  MappingDesc::SHADOW
    0x29000000000ULL-0x2A000000000ULL  MappingDesc::ORIGIN
    0x2A000000000ULL-0x2B000000000ULL  MappingDesc::APP
    0x2B000000000ULL-0x2C000000000ULL  MappingDesc::INVALID
    0x2C000000000ULL-0x2D000000000ULL  MappingDesc::SHADOW
    0x2D000000000ULL-0x2E000000000ULL  MappingDesc::ORIGIN
    0x2E000000000ULL-0x2F000000000ULL  MappingDesc::APP
    0x2F000000000ULL-0x39000000000ULL  MappingDesc::INVALID
    0x39000000000ULL-0x3A000000000ULL  MappingDesc::SHADOW
    0x3A000000000ULL-0x3B000000000ULL  MappingDesc::ORIGIN
    0x3B000000000ULL-0x3C000000000ULL  MappingDesc::APP
    0x3C000000000ULL-0x3D000000000ULL  MappingDesc::INVALID
    0x3D000000000ULL-0x3E000000000ULL  MappingDesc::SHADOW
    0x3E000000000ULL-0x3F000000000ULL  MappingDesc::ORIGIN
    0x3F000000000ULL-0x40000000000ULL  MappingDesc::APP

And although complex it provides a better memory utilization that
previous one.

llvm-svn: 251624