Pseudolocale support for grammatical gender

Default behavior is generate grammatical gender strings with different
prefix when pseudolocale is enabled. Also extend two specifiers to
support generate grammatical gender string for a specific gender and for
a spefific ratio. go/pseudolocale-support-for-grammatical-gender

Bug: b/272626712
Test: Added and verified affected atests pass
Change-Id: I6b7514425898facb68f0b1f6fb09e4f87978c03d