Migrate GUI colors test to original CSS color format

[GuillaumeGomez]

Follow-up of #111459.

r? @notriddle

[notriddle]

@bors r+ rollup

[bors]

📌 Commit e06633f has been approved by notriddle

It is now in the queue for this repository.

[bors]

⌛ Testing commit e06633f with merge 8771282...

[bors]

☀️ Test successful - checks-actions
Approved by: notriddle
Pushing 8771282 to master...

[rust-timer]

Finished benchmarking commit (8771282): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.7%	[-0.7%, -0.6%]	4
Improvements ✅ (secondary)	-0.5%	[-0.6%, -0.3%]	6
All ❌✅ (primary)	-0.7%	[-0.7%, -0.6%]	4

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	2.6%	[2.6%, 2.6%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.6%	[2.6%, 2.6%]	1

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.3%	[2.3%, 2.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 651.923s -> 651.225s (-0.11%)