Regres main.go cleanup
Regres main.go cleanup

This CL applies the suggestion from:
https://swiftshader-review.googlesource.com/c/SwiftShader/+/60768/1#message-08ce82ada4a8fb6581f3427c0aabe5f32e1359d6

and unifies the config structures into a new DeqpConfig struct to avoid future issues.

Bug: b/201453797
Change-Id: I75539852a770949a09aeb1694a17d09ddd3890ac
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/68709
Reviewed-by: Ben Clayton <1f693eb7158dc33015048c09d6712f74dabddf79@google.com>
Tested-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Kokoro-Result: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Presubmit-Ready: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Commit-Queue: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>

google/swiftshader,google/swiftshader,google/swiftshader