Add npm capability to NodeTool

[sunahe]

Resolves #9795

[msftclas]

All CLA requirements met.

[damccorm]

I agree this is an issue that should be addressed, I think the solution is a little more complicated than this though. At the moment I don't think we actually acquire Npm as part of this task, so we can't just mark it as being satisfied

[sunahe]

Doesn't it? At least all the redistributable packages on https://nodejs.org/dist/v10.15.3/ seem to contain both node and npm executables. I tried using the updated task (on a Windows build agent), and there npm was successfully found and used. Here are the relevant build logs from npm tasks in that build:

2019-03-11T21:02:22.7270898Z [command]C:\windows\system32\cmd.exe /D /S /C "D:\B\A1\_work\_tool\node\10.15.3\x64\npm.cmd --version"
2019-03-11T21:02:26.0551038Z 6.4.1
2019-03-11T21:02:29.4926304Z [command]C:\windows\system32\cmd.exe /D /S /C "D:\B\A1\_work\_tool\node\10.15.3\x64\npm.cmd config list"
2019-03-11T21:02:30.6830756Z ; cli configs
2019-03-11T21:02:30.6831541Z metrics-registry = "https://registry.npmjs.org/"
2019-03-11T21:02:30.6831879Z scope = ""
2019-03-11T21:02:30.6832363Z user-agent = "npm/6.4.1 node/v10.15.3 win32 x64"
2019-03-11T21:02:30.6832687Z 
2019-03-11T21:02:30.6833153Z ; environment configs
2019-03-11T21:02:30.6833666Z userconfig = "D:\\B\\A1\\_work\\260\\npm\\161912.npmrc"
2019-03-11T21:02:30.6833995Z 
2019-03-11T21:02:30.6834488Z ; node bin location = D:\B\A1\_work\_tool\node\10.15.3\x64\node.exe
2019-03-11T21:02:30.6835054Z ; cwd = D:\B\A1\_work\260\s\frontend
2019-03-11T21:02:30.6836414Z ; HOME = C:\Users\TFSBUILD
2019-03-11T21:02:30.6836959Z ; "npm config ls -l" to show all defaults.
2019-03-11T21:02:30.6837302Z 
2019-03-11T21:02:30.6840230Z [command]C:\windows\system32\cmd.exe /D /S /C "D:\B\A1\_work\_tool\node\10.15.3\x64\npm.cmd run build"

[damccorm]

Interesting. I first noticed this behavior on older versions of node on windows, I think its actually only true for them because Node doesn't package npm with them in older releases. You can see we have a fallback to the older format for windows node in our code, I think just those don't get npm installed. That's still an issue, but less concerning.