Field "X86" has no lowercase runes and was being left uppercase.
Change the new PropertyNameForField rules to lowercase the name unless
it has any uppercase rune after the first rune (which is always
uppercase) and no lowercase runes.
Bug: 148865218
Test: proptools_test.go
Change-Id: Ifd1c10fc03f5ae1765d25b3f73dba8fd61c5c956
Soong config variables may propagate an uppercase name from Make.
Blueprint properties have traditionally been all lowercase, and
using an uppercase property struct field name resulted in a strange
Blueprint property name with the first rune lowercase and the
remaining runes uppercase.
Update the rules for proptools.PropertyNameForField to not lowercase
the first rune if the field name has mulitple runes and is not all
uppercase.
Fixes: 148865218
Test: proptools_test.go
Change-Id: I8de2f65ffb00e5a8ce0aea0caf09f5859315f6b8
