[browser] profiler setup and env variables

[pavelsavara]

• set DOTNET_DiagnosticPorts by DiagnosticPorts MSBuild property, same as other mono platforms
• new WasmEnvironmentVariable item list
• new WasmAppBuilder.EnvVariables
• set FeaturePerfTracing when WasmPerfTracing
• fixed enablePerfTracing || enableBrowserProfiler for profiler events cwraps
• simplified mono profilers setup
• split LogProfilerTest and BrowserProfilerTest

Contributes to #76316

[dotnet-policy-service]

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PR Overview

This PR enhances the WebAssembly profiler setup and environment variable configuration for .NET by refining profiler initialization, updating test assets, and modifying runtime and build tasks to better support browser and log profilers.

• Introduces a new EnvVariables item in WasmAppBuilder and updates BootJsonData to use a Dictionary for environment variables.
• Splits and renames profiler tests to clearly separate LogProfiler and BrowserProfiler scenarios.
• Adjusts runtime initialization and cwraps configuration to support new profiler setup logic.

Reviewed Changes

File	Description
src/mono/wasm/testassets/WasmBasicTestApp/App/BrowserProfilerTest.cs	Adds a new browser profiler test.
src/mono/wasm/Wasm.Build.Tests/DiagnosticsTests.cs	Renames and updates tests for log and browser profiler support.
src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js	Updates test case names and profiler configuration strings.
src/tasks/WasmAppBuilder/WasmAppBuilder.cs	Adds EnvVariables property and integrates it into boot.json generation.
src/mono/browser/runtime/profiler.ts	Refactors profiler initialization logic for log profiler.
src/mono/browser/runtime/startup.ts	Updates environment variable and profiler initialization logic.
src/mono/browser/runtime/cwraps.ts	Adjusts condition for including profiler cwraps based on profiler configuration.
src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/BootJsonData.cs	Changes environmentVariables type from object to Dictionary for clarity.
src/mono/browser/runtime/es6/dotnet.es6.lib.js	Cleans up profiler and runtime configuration properties.
src/mono/wasm/testassets/WasmBasicTestApp/App/LogProfilerTest.cs	Renames test class to align with log profiler testing.
src/mono/browser/runtime/jiterpreter.ts	Updates condition to include browser profiler support in jiterpreter profiling.

Copilot reviewed 14 out of 14 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (1)

src/mono/browser/runtime/profiler.ts:46

• Since the assertion guarantees that options.takeHeapshot is defined, the subsequent 'if (options.takeHeapshot)' check and its else branch may be redundant. Consider refactoring this conditional to streamline the logic.

mono_assert(options.takeHeapshot, "Log profiler is not enabled, the takeHeapshot method must be defined in LogProfilerOptions.takeHeapshot");

[javiercn]

Changes look good to me, nothing strikes me as incorrect, although I don't have a lot of context.

My understanding is that this is enabled through the build, and then flows down to the runtime, with the most relevant change being the ability to add environment variables through the build on demand (which was not possible before).

Am I missing something?

[pavelsavara]

(which was not possible before).

It was/is possible on runtime, there is JS and managed API for it.
It was also possible to hack it via specially crafted value of WasmExtraConfig msbuild items. But it's very clumsy.