Add pseudo async Create*PipelineAsync methods

[sagudev]

Renewed #31194

It also includes WebGPU CTS update to gpuweb/cts@ad066ef with a lot of stabilization:

• flaky PASS/FAIL, TIMEOUT, NOTRUN are disabled,
• using patched moz-webgpu-cts for expectations managing
• currently webgpu:shader,execution,expression occasionally cause crashes but this is being investigated as part of Ocassional crash in hashbrown when using hash{map, set} in script_module.rs when advancing modules #31397

---

• ./mach build -d does not report any errors
• ./mach test-tidy does not report any errors
• There are tests for these changes in CTS

[github-actions]

🔨 Triggering try run (#8295983938) for WebGPU CTS

[github-actions]

Test results for linux-wpt-layout-2020 from try job (#8295983938):

Flaky unexpected result (25)

• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,af_comparison:less_than:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,af_multiplication:vector_scalar:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,f16_remainder:scalar_vector:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,f32_matrix_subtraction:matrix:*
• CRASH [expected TIMEOUT] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,f32_matrix_vector_multiplication:matrix_vector:*
• CRASH [expected TIMEOUT] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,f32_matrix_vector_multiplication:vector_matrix:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,f32_multiplication:scalar_compound:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,f32_remainder:scalar:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,f32_subtraction:scalar:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,u32_arithmetic:addition_scalar_vector:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,u32_arithmetic:division_vector_scalar:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,asin:f32:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,atan:abstract_float:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,cos:f32:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,dot:abstract_int:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,max:abstract_int:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,min:f16:*
• CRASH [expected TIMEOUT] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,mix:f32_nonmatching_vec2:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,sinh:f16:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,smoothstep:f32:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,tan:abstract_float:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,tanh:f16:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,unpack4x8snorm:unpack:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,unary,f16_conversion:f32_mat:*
• CRASH [expected TIMEOUT] /_webgpu/webgpu/webgpu/web_platform/reftests/canvas_image_rendering.https.html

Stable unexpected results (8)

• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,f32_multiplication:vector_scalar:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,f32_subtraction:scalar_compound:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,binary,i32_arithmetic:multiplication_vector_scalar:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,ceil:abstract_float:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,exp2:f32:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,length:f16_vec4:*
• CRASH [expected ERROR] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,reflect:f32_vec4:*
• CRASH [expected OK] /_webgpu/webgpu/cts.https.html?q=webgpu:shader,execution,expression,call,builtin,transpose:f16:*

[github-actions]

⚠️ Try run (#8295983938) failed.

[sagudev]

Test results for linux-wpt-layout-2020 from try job (#8295983938):
Flaky unexpected result (25)
Stable unexpected results (8)

As noted in PR summary all fails (except one flake) are webgpu:shader,execution,expression and I think this is as good as it gets, for now.

[gterzian]

DOM methods stubs LGTM. I didn't look at the test changes(the actual changes to test code),why are those necessary?

[sagudev]

I didn't look at the test changes(the actual changes to test code),why are those necessary?

Thoes are actually coming from upstream (some things were needed for stabilization of results).