Don't change Instawhip Recharge's scale every tic (also minor stuff)

Changes include:

• Scale check so they don't keep changing scale when they don't need to.
• Removed x->tics = 1 because the spawnstate already took one tic to finish anyway.
• Spawned mobj has the height offset from the start.
• Fix instawhip-related visuals being wrongly offset when gravflipped.

Before (see FPS counter):

beforewhip ringracers0153

After:

afterwhip ringracers0158

Changelog:

• Fixed Instawhip causing framerate drops during the process of being charged.
• Fixed Instawhip visuals being wrongly positioned during Reverse Gravity sections.