Rename ARM 4.8 compilers...they're now 5.4 compilers.
Rename ARM 4.8 compilers...they're now 5.4 compilers.

Aliases the 48s to these, though that's a little disingenuous.

Addresses #155

mattgodbolt/compiler-explorer,mattgodbolt/compiler-explorer,dkm/gcc-explorer,ibuclaw/gcc-explorer,mattgodbolt/compiler-explorer,dkm/gcc-explorer,dkm/gcc-explorer,mattgodbolt/gcc-explorer,mattgodbolt/compiler-explorer,mattgodbolt/gcc-explorer,ibuclaw/gcc-explorer,mattgodbolt/compiler-explorer,ibuclaw/gcc-explorer,mattgodbolt/gcc-explorer,mattgodbolt/compiler-explorer,dkm/gcc-explorer,dkm/gcc-explorer,ibuclaw/gcc-explorer,dkm/gcc-explorer,mattgodbolt/compiler-explorer,dkm/gcc-explorer,dkm/gcc-explorer,mattgodbolt/gcc-explorer,mattgodbolt/compiler-explorer,ibuclaw/gcc-explorer,dkm/gcc-explorer,mattgodbolt/gcc-explorer