gh-99108: Disable HACL SIMD code on older versions of Android

[mhsmith]

The build is currently failing on Android x86-64:

/home/buildbot/android-sdk/ndk/26.2.11394342/toolchains/llvm/prebuilt/linux-x86_64/bin/x86_64-linux-android21-clang -c -I../../../Modules/_hacl -I../../../Modules/_hacl/include -D_BSD_SOURCE -D_DEFAULT_SOURCE -fno-strict-overflow
 -Wsign-compare -Wunreachable-code -DNDEBUG -g -O3 -Wall -I/home/buildbot/git/python/cpython/cross-build/x86_64-linux-android/prefix/include  -I/home/buildbot/git/python/cpython/cross-build/x86_64-linux-android/prefix/include  -s
td=c11 -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden  -I../../../Include/internal -I../../../Include/internal/mimalloc -IObjects -IIncl
ude -IPython -I. -I../../../Include   -fPIC -fPIC -DLINUX_NO_EXPLICIT_BZERO -msse -msse2 -msse3 -msse4.1 -msse4.2 -DHACL_CAN_COMPILE_VEC128 -o Modules/_hacl/Hacl_Hash_Blake2s_Simd128.o ../../../Modules/_hacl/Hacl_Hash_Blake2s_Sim
d128.c
../../../Modules/_hacl/Hacl_Hash_Blake2s_Simd128.c:589:40: error: call to undeclared library function 'aligned_alloc' with type 'void *(unsigned long, unsigned long)'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    (Lib_IntVector_Intrinsics_vec128 *)KRML_ALIGNED_MALLOC(16,
                                       ^
../../../Modules/_hacl/include/krml/internal/target.h:133:39: note: expanded from macro 'KRML_ALIGNED_MALLOC'
#    define KRML_ALIGNED_MALLOC(X, Y) aligned_alloc(X, Y)

This is because aligned_alloc was only added to Android in API level 28, while we're building against level 21. So this PR disables the SIMD code completely when building against older Android versions.

• Issue: Replace built-in hashlib with verified implementations from HACL* #99108

[mhsmith]

!buildbot android

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @mhsmith for commit 198a0b9 🤖

The command will test the builders whose names match following regular expression: android

The builders matched are:

• AMD64 Android PR
• aarch64 Android PR

[mhsmith]

The x86-64 builder wasn't ready earlier, but it's passed now.

[freakboy3742]

LGTM!