Use UTF8 encoding for strings NetJavaImpl (#5144)
Use UTF8 encoding for strings NetJavaImpl (#5144)

* Use UTF8 encoding for POST contents in NetJavaImpl for string based requests.

* Use UTF8 for response strings in NetJavaImpl

bladecoder/libgdx,alex-dorokhov/libgdx,libgdx/libgdx,NathanSweet/libgdx,stinsonga/libgdx,MikkelTAndersen/libgdx,cypherdare/libgdx,alex-dorokhov/libgdx,MikkelTAndersen/libgdx,tommyettinger/libgdx,stinsonga/libgdx,Zomby2D/libgdx,MikkelTAndersen/libgdx,libgdx/libgdx,alex-dorokhov/libgdx,MikkelTAndersen/libgdx,MikkelTAndersen/libgdx,alex-dorokhov/libgdx,bladecoder/libgdx,libgdx/libgdx,alex-dorokhov/libgdx,MikkelTAndersen/libgdx,Zomby2D/libgdx,tommyettinger/libgdx,MikkelTAndersen/libgdx,cypherdare/libgdx,tommyettinger/libgdx,bladecoder/libgdx,Zomby2D/libgdx,bladecoder/libgdx,MikkelTAndersen/libgdx,tommyettinger/libgdx,NathanSweet/libgdx,alex-dorokhov/libgdx,stinsonga/libgdx,bladecoder/libgdx,Zomby2D/libgdx,NathanSweet/libgdx,stinsonga/libgdx,cypherdare/libgdx,tommyettinger/libgdx,cypherdare/libgdx,libgdx/libgdx,NathanSweet/libgdx,cypherdare/libgdx,Zomby2D/libgdx,alex-dorokhov/libgdx,stinsonga/libgdx,alex-dorokhov/libgdx,NathanSweet/libgdx,libgdx/libgdx