Regres fetches HEAD and truncates deqp.json
Regres fetches HEAD and truncates deqp.json

Regres was fetching the wrong reference and getting a hash of 0 as a
result. Furthermore, instead of overwriting deqp.json, it was appending
the incorrect hash. This fix should fetch the correct hash from the
latest revision of dEQP's master branch.

Bug: b/201453797
Change-Id: Iac2d8d979fa9f4df6722899cc514384455c366b0
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/59549
Kokoro-Result: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Reviewed-by: Ben Clayton <1f693eb7158dc33015048c09d6712f74dabddf79@google.com>
Tested-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>

google/swiftshader,google/swiftshader,google/swiftshader