On a 4-core Linux VM it has the following effect:

LESS_DEBUG_INFO=0
real	20m13.051s
user	63m45.648s
sys	6m51.636s
745.8 MB libvk_swiftshader.so
13 GB build dir

LESS_DEBUG_INFO=1
real	15m2.821s
user	51m8.659s
sys	5m17.466s
197.8 MB libvk_swiftshader.so
3.1 GB build dir

Also use /DEBUG:FASTLINK on Visual Studio. It disables producing a
single .pdb which can be relocated.

Specifying LESS_DEBUG_INFO=1 has no effect on Windows currently, but is
done for consistency and in case we start using Clang on Windows.

Also color errors in presubmit consistently.

Bug: b/147735529
Change-Id: Ieb5c84c192178653f74043daf3d8ee599d3ecf6b
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/40228
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>