Revert std.crypto kangarootwelve addition

I would like a chance to review this before it lands, please. Feel free
to submit the work again without changes and I will make review
comments.

In the meantime, these reverts avoid intermittent CI failures, and
remove bad patterns from occurring in the standard library that other
users might copy.

Revert "std.crypto: improve KT documentation, use key_length for B3 key length (#25807)"

This reverts commit 4b593a6.

Revert "crypto - threaded K12: separate context computation from thread spawning (#25793)"

This reverts commit ee4df4a.

Revert "crypto.kt128: when using incremental hashing, use SIMD when possible (#25783)"

This reverts commit bf90825.

Revert "Add std.crypto.hash.sha3.{KT128,KT256} - RFC 9861. (#25593)"

This reverts commit 95c76b1.

Author: andrewrk

lib/std/crypto/benchmark.zig

@@ -30,15 +30,13 @@ const hashes = [_]Crypto{
     Crypto{ .ty = crypto.hash.sha3.Shake256, .name = "shake-256" },
     Crypto{ .ty = crypto.hash.sha3.TurboShake128(null), .name = "turboshake-128" },
     Crypto{ .ty = crypto.hash.sha3.TurboShake256(null), .name = "turboshake-256" },
-    Crypto{ .ty = crypto.hash.sha3.KT128, .name = "kt128" },
     Crypto{ .ty = crypto.hash.blake2.Blake2s256, .name = "blake2s" },
     Crypto{ .ty = crypto.hash.blake2.Blake2b512, .name = "blake2b" },
     Crypto{ .ty = crypto.hash.Blake3, .name = "blake3" },
 };
 
 const parallel_hashes = [_]Crypto{
     Crypto{ .ty = crypto.hash.Blake3, .name = "blake3-parallel" },
-    Crypto{ .ty = crypto.hash.sha3.KT128, .name = "kt128-parallel" },
 };
 
 const block_size: usize = 8 * 8192;

lib/std/crypto/blake3.zig

@@ -12,8 +12,8 @@ const Vec16 = @Vector(16, u32);
 const chunk_length = 1024;
 const max_depth = 54;
 
-const simd_degree = std.simd.suggestVectorLength(u32) orelse 1;
-const max_simd_degree = simd_degree;
+pub const simd_degree = std.simd.suggestVectorLength(u32) orelse 1;
+pub const max_simd_degree = simd_degree;
 const max_simd_degree_or_2 = if (max_simd_degree > 2) max_simd_degree else 2;
 
 /// Threshold for switching to parallel processing.
@@ -502,7 +502,9 @@ fn hashManySimd(
     var out_ptr = out.ptr;
     var cnt = counter;
 
-    if (simd_degree >= 16) {
+    const simd_deg = comptime simd_degree;
+
+    if (comptime simd_deg >= 16) {
         while (remaining >= 16) {
             const sixteen_inputs = [16][*]const u8{
                 inp[0],  inp[1],  inp[2],  inp[3],
@@ -523,7 +525,7 @@ fn hashManySimd(
         }
     }
 
-    if (simd_degree >= 8) {
+    if (comptime simd_deg >= 8) {
         while (remaining >= 8) {
             const eight_inputs = [8][*]const u8{
                 inp[0], inp[1], inp[2], inp[3],
@@ -542,7 +544,7 @@ fn hashManySimd(
         }
     }
 
-    if (simd_degree >= 4) {
+    if (comptime simd_deg >= 4) {
         while (remaining >= 4) {
             const four_inputs = [4][*]const u8{
                 inp[0],
@@ -569,7 +571,7 @@ fn hashManySimd(
 }
 
 fn hashMany(inputs: [][*]const u8, num_inputs: usize, blocks: usize, key: [8]u32, counter: u64, increment_counter: bool, flags: Flags, flags_start: Flags, flags_end: Flags, out: []u8) void {
-    if (max_simd_degree >= 4) {
+    if (comptime max_simd_degree >= 4) {
         hashManySimd(inputs, num_inputs, blocks, key, counter, increment_counter, flags, flags_start, flags_end, out);
     } else {
         hashManyPortable(inputs, num_inputs, blocks, key, counter, increment_counter, flags, flags_start, flags_end, out);
@@ -907,7 +909,7 @@ pub const Blake3 = struct {
     pub const digest_length = 32;
     pub const key_length = 32;
 
-    pub const Options = struct { key: ?[key_length]u8 = null };
+    pub const Options = struct { key: ?[digest_length]u8 = null };
     pub const KdfOptions = struct {};
 
     key: [8]u32,