fix: ANDROID_HOME is the new default, to check first and give advice

[ath0mas]

Platforms affected

Android

Motivation and Context

cordova-android 11.0.0 (since #1444) reports about Android SDK: undefined while ANDROID_HOME is set and ANDROID_SDK_ROOT is not.

Description

cordova create hello com.example.hello HelloWorld
cd hello/
cordova platform add [email protected]
cordova build

with environment variables set for Java (JAVA_HOME) and Android (ANDROID_HOME, and no more ANDROID_SDK_ROOT)

results in a successful build but with wrong reporting during the first steps:

Checking Java JDK and Android SDK versions
ANDROID_HOME=C:\my\path\to\android-sdk (recommended setting)
ANDROID_SDK_ROOT=undefined (DEPRECATED)
Using Android SDK: undefined

Testing

• creating and building a blank project using local clone of my fork of cordova-android
• npm run test

Checklist

• [x] I've run the tests to see all new and existing tests pass
• [x] I added automated test coverage as appropriate for this change
• [x] Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• [x] If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• [x] I've updated the documentation if necessary

[codecov-commenter]

Codecov Report

Merging #1471 (b06f3db) into master (60e3803) will not change coverage. The diff coverage is 50.00%.

@@           Coverage Diff           @@
##           master    #1471   +/-   ##
=======================================
  Coverage   72.25%   72.25%           
=======================================
  Files          21       21           
  Lines        1748     1748           
=======================================
  Hits         1263     1263           
  Misses        485      485           

Impacted Files	Coverage Δ
lib/check_reqs.js	71.05% <50.00%> (ø)

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[breautek]

Final call for review before merging.

[breautek]

Thank you @ath0mas for helping us keep up with Android tooling standards.