Clean up no-op cipher aliases for legacy SHA-2 CBC ciphers

These cipher aliases were not hooked up to anything, and can be
cleaned up following the deprecation of corresponding ciphers in 2018.

Update-Note: "SHA256" and "SHA384" are no longer valid aliases in the
cipher string for cipher suite configuration. They will be rejected
by SSL{_CTX}_set_strict_cipher_list. They had already been no-ops, i.e.
not corresponding to any ciphers, since 2018.

Change-Id: I29fcc3c7567f24a78cf049156520499e6a6a6964
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/86688
Reviewed-by: David Benjamin <davidben@google.com>
Auto-Submit: Lily Chen <chlily@google.com>
Commit-Queue: Lily Chen <chlily@google.com>

ssl/ssl_cipher.cc

diff --git a/ssl/ssl_cipher.cc b/ssl/ssl_cipher.cc
index 1cda428..1ef231c 100644
--- a/ssl/ssl_cipher.cc
+++ b/ssl/ssl_cipher.cc
@@ -454,11 +454,6 @@
     // Legacy strength classes.
     {"HIGH", ~0u, ~0u, ~0u, ~0u, 0},
     {"FIPS", ~0u, ~0u, ~0u, ~0u, 0},
-
-    // Temporary no-op aliases corresponding to removed SHA-2 legacy CBC
-    // ciphers. These should be removed after 2018-05-14.
-    {"SHA256", 0, 0, 0, 0, 0},
-    {"SHA384", 0, 0, 0, 0, 0},
 };
 
 static const size_t kCipherAliasesLen = std::size(kCipherAliases);