nir/print: group hex and float vectors together

nir/print: group hex and float vectors together

Vectors are much easier to follow in this format, because developer cares
either about hex or float values, never both.

Before/after:

-vec4 32 ssa_222 = load_const (0x00000000 /* 0.000000 */, 0x00000000 /* 0.000000 */, 0x3f800000 /* 1.000000 */, 0x3f800000 /* 1.000000 */)
+vec4 32 ssa_222 = load_const (0x00000000, 0x00000000, 0x3f800000, 0x3f800000) = (0.000000, 0.000000, 1.000000, 1.000000)

-vec1 32 ssa_174 = load_const (0xbf800000 /* -1.000000 */)
+vec1 32 ssa_174 = load_const (0xbf800000 = -1.000000)

Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13880>