Add test to the MapParser class in OTA_analyzer.

Add unit test to the MapParser class in map_parser.js. Please refer to
this CL for the original class definition:

https://android-review.googlesource.com/c/platform/development/+/1760909

Test: npm run test:unit
Change-Id: I2d640e9c5e27c0a012e32b4be09348034b67b235
3 files changed