Merge bitcoin/bitcoin#28893: Fix SSE4.1-related issues

d440f13db0 crypto: Guard code with `ENABLE_SSE41` macro (Hennadii Stepanov)
6ec1ca7c85 build: Fix test for SSE4.1 intrinsics (Hennadii Stepanov)

Pull request description:

  1. Fix the test for SSE4.1 intrinsics during build system configuration, which currently can be false positive, for example, when `CXXFLAGS="-mno-sse4.1"` provided.

  This PR fixes the test by adding the `_mm_blend_epi16` SSE4.1 function used in our codebase.

  2. Guard `sha_x86_shani.cpp` code with `ENABLE_SSE41` macro as it uses the `_mm_blend_epi16` function from
  the SSE4.1 instruction set.

  It is possible that SHA-NI is enabled even when SSE4.1 is disabled, which causes compile errors in the master branch.

  Closes https://github.com/bitcoin/bitcoin/issues/28864.

ACKs for top commit:
  sipa:
    utACK d440f13db0
  willcl-ark:
    tACK d440f13db0
  theuni:
    utACK d440f13db0

Tree-SHA512: a6e1e8c94e1b94874ff51846815ef445e6135cbdb01b08eb695b3548115f2340dd835ebe53673ae46a553fe6be4815e68d8642c34235dd7af5106c4b7c9ea6f3

src/crypto/sha256.cpp

@@ -621,7 +621,7 @@ std::string SHA256AutoDetect(sha256_implementation::UseImplementation use_implem
         }
     }
 
-#if defined(ENABLE_X86_SHANI)
+#if defined(ENABLE_SSE41) && defined(ENABLE_X86_SHANI)
     if (have_x86_shani) {
         Transform = sha256_x86_shani::Transform;
         TransformD64 = TransformD64Wrapper<sha256_x86_shani::Transform>;

src/crypto/sha256_x86_shani.cpp

@@ -6,7 +6,7 @@
 // Written and placed in public domain by Jeffrey Walton.
 // Based on code from Intel, and by Sean Gulley for the miTLS project.
 
-#ifdef ENABLE_X86_SHANI
+#if defined(ENABLE_SSE41) && defined(ENABLE_X86_SHANI)
 
 #include <stdint.h>
 #include <immintrin.h>