core/crypto: Change hash asserts to panics

Assertions can be disabled, but at the point where cryptographic
anything is involved, a single branch has an infinitesimally small
performance impact.

The correct thing to do is to punch the caller in the face if they do
something that is blatantly incorrect, especially in a security critical
setting.

core/crypto/_blake2/blake2.odin

@@ -180,11 +180,17 @@ update :: proc "contextless" (ctx: ^$T, p: []byte) {
 	ctx.nx += copy(ctx.x[ctx.nx:], p)
 }
 
-final :: proc "contextless" (ctx: ^$T, hash: []byte) {
+final :: proc(ctx: ^$T, hash: []byte) {
 	when T == Blake2s_Context {
+		if len(hash) < BLAKE2S_SIZE {
+			panic("crypto/blake2s: invalid destination digest size")
+		}
 		blake2s_final(ctx, hash)
 	}
 	when T == Blake2b_Context {
+		if len(hash) < BLAKE2B_SIZE {
+			panic("crypto/blake2b: invalid destination digest size")
+		}
 		blake2b_final(ctx, hash)
 	}
 }