[wasm] Review `FROZEN_CACHE` setting in the build targets

[radical]

This whole does need to be reviewed again. If the workload is installed in non-user-writable location then how does the build behave? How does the FROZEN_CACHE setting affect things?

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Issue Details

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This whole does need to be reviewed again. If the workload is installed in non-user-writable location then how does the build behave? How does the FROZEN_CACHE setting affect things?

Author:	radical
Assignees:	-
Labels:	arch-wasm, area-Build-mono
Milestone:	-

[lewing]

This is more important in the emsdk build when we make the cache package

[lambdageek]

This is causing breakages on lanes like this runtime-wasm (Build browser-wasm linux Release LibraryTests_NodeJs):

cache(0,0): error : (NETCORE_ENGINEERING_TELEMETRY=Build) Accessing the Emscripten cache at "/usr/local/emscripten/emsdk/upstream/emscripten/cache" (for "sysroot/lib/wasm32-emscripten/libsqlite3.a") is taking a long time, another process should be writing to it. If there are none and you suspect this process has deadlocked, try deleting the lock file "/usr/local/emscripten/emsdk/upstream/emscripten/cache/cache.lock" and try again. If this occurs deterministically, consider filing a bug.

[lambdageek]

the cache must be frozen. If Emscripten is complaining about missing libraries, then we need to update the nuget pack to include them. not to unfreeze the cache

[lambdageek]

the $(_EmBuilder) build MINIMAL stuff from WasmApp.Native.targets should be done in emsdk, not in dotnet/runtime - all that stuff should end up in the Cache nuget

[radical]

build MINIMAL was removed from WasmApp.Native.targets. The only instance of *FROZEN_CACHE in our targets is:

runtime/src/mono/wasm/build/WasmApp.Native.targets

Lines 274 to 275 in 81cb4b8

	<EmscriptenEnvVars Include="EM_CACHE=$(WasmCachePath)" Condition="'$(WasmCachePath)' != ''" />
	<EmscriptenEnvVars Include="EM_FROZEN_CACHE=True" />

• Is EM_FROZEN_CACHE just the new name for FROZEN_CACHE?
• If the workload is installed in non-user-writable location then how does the build behave? How does the EM_FROZEN_CACHE setting affect things?