treewide: update LLVM Bugzilla links

LLVM moved their issue tracker from their own Bugzilla instance to GitHub
issues.  While all of the links are still valid, they may not necessarily
show the most up to date information around the issues, as all updates
will occur on GitHub, not Bugzilla.

Another complication is that the Bugzilla issue number is not always the
same as the GitHub issue number.  Thankfully, LLVM maintains this mapping
through two shortlinks:

  https://llvm.org/bz<num> -> https://bugs.llvm.org/show_bug.cgi?id=<num>
  https://llvm.org/pr<num> -> https://github.com/llvm/llvm-project/issues/<mapped_num>

Switch all "https://bugs.llvm.org/show_bug.cgi?id=<num>" links to the
"https://llvm.org/pr<num>" shortlink so that the links show the most up to
date information.  Each migrated issue links back to the Bugzilla entry,
so there should be no loss of fidelity of information here.

Link: https://lkml.kernel.org/r/20240109-update-llvm-links-v1-3-eb09b59db071@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Fangrui Song <maskray@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Mykola Lysenko <mykolal@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/stackinit_kunit.c

@@ -404,7 +404,7 @@ static noinline int leaf_switch_2_none(unsigned long sp, bool fill,
  * These are expected to fail for most configurations because neither
  * GCC nor Clang have a way to perform initialization of variables in
  * non-code areas (i.e. in a switch statement before the first "case").
- * https://bugs.llvm.org/show_bug.cgi?id=44916
+ * https://llvm.org/pr44916
  */
 DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR, ALWAYS_FAIL);
 DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR, ALWAYS_FAIL);