Parse both macOS and Mac OS X SDK names

[jmagman]

In older Xcode bundles the SDK productName is Mac OS X, not macOS. Instead of parsing productName, parse platform, but filter out DriverKit. Regressed in #528.

Needs to handle these:

  {
    "canonicalName" : "driverkit.macosx19.0",
    "displayName" : "DriverKit 19.0",
    "isBaseSdk" : true,
    "platform" : "macosx",
    "platformPath" : "/Users/m/xcode-cipd/Xcode-12A7209.app/Contents/Developer/Platforms/MacOSX.platform",
    "platformVersion" : "10.15.6",
    "sdkPath" : "/Users/m/xcode-cipd/Xcode-12A7209.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/DriverKit19.0.sdk",
    "sdkVersion" : "19.0"
  },
  {
    "canonicalName" : "macosx11.1",
    "displayName" : "macOS 11.1",
    "iOSSupportVersion" : "14.3",
    "isBaseSdk" : true,
    "platform" : "macosx",
    "platformPath" : "/Users/m/xcode-cipd/Xcode-12A7209.app/Contents/Developer/Platforms/MacOSX.platform",
    "platformVersion" : "10.15.6",
    "productBuildVersion" : "20C63",
    "productCopyright" : "1983-2020 Apple Inc.",
    "productName" : "macOS",
    "productUserVisibleVersion" : "11.1",
    "productVersion" : "11.1",
    "sdkPath" : "/Users/m/xcode-cipd/Xcode-12A7209.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.1.sdk",
    "sdkVersion" : "11.1"
  },
  {
    "canonicalName" : "macosx10.15",
    "displayName" : "macOS 10.15",
    "iOSSupportVersion" : "13.6",
    "isBaseSdk" : true,
    "platform" : "macosx",
    "platformPath" : "/opt/s/w/ir/cache/osx_sdk/XCode.app/Contents/Developer/Platforms/MacOSX.platform",
    "platformVersion" : "10.15.6",
    "productBuildVersion" : "19G68",
    "productCopyright" : "1983-2020 Apple Inc.",
    "productName" : "Mac OS X",
    "productUserVisibleVersion" : "10.15.6",
    "productVersion" : "10.15.6",
    "sdkPath" : "/opt/s/w/ir/cache/osx_sdk/XCode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk",
    "sdkVersion" : "10.15.6"
  },

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