Rename soong.environment.used with product name

From the previous work on renaming build.ninja, it was found that there
are extra dependencies from build.ninja which can be varied by
TARGET_PRODUCT : which is soong.environment.used.<tag>. This change
renames soong.environment.used to have target product between 'used' and
'<tag>' if available.

Bug: 277029044
Test: Test confirmed that build.ninja is not being re-generated
Change-Id: I987b6bd1a8b4f06dac52537e4178d8556251d254