tsc -w should not clear screen if I don't want it to

[iffy]

Issue #13020 makes tsc -w always clear the screen. This is annoying when:

• tsc -w is part of several processes being run in the same terminal
• I care about previous output.

Expected behavior:

tsc -w should not clear the screen before every compile if a certain additional flag is provided.

Actual behavior:

tsc -w always clears the screen before compilation.

Related Issues:

• tsc -w should clear screen before each run #13020

[j-oliveras]

Duplicate or related to #21295.

[roblav96]

@mhegazy Just merge the #21303 @JoshuaKGoldberg

[mhegazy]

already tracked by #21295.