Add sancov support for large AArch64 binaries. (#185374)

In AArch64 calls have a +/-128MB range

(https://developer.arm.com/documentation/ddi0602/2025-12/Base-Instructions/BL--Branch-with-link-).
In cases where the .text is larger than that, the linker adds functions
that just jumps to the sanitizer functions and places them to some code
location where the rest of the binary can call it. These functions have
the prefix __AArch64ADRPThunk__.
This commit marks calls to this function as coverage points.

llvm/tools/sancov/sancov.cpp

diff --git a/llvm/tools/sancov/sancov.cpp b/llvm/tools/sancov/sancov.cpp
index f2e71f9..ec069a2 100644
--- a/llvm/tools/sancov/sancov.cpp
+++ b/llvm/tools/sancov/sancov.cpp
@@ -628,7 +628,12 @@
          // Mac has '___' prefix
          Name == "___sanitizer_cov" || Name == "___sanitizer_cov_with_check" ||
          Name == "___sanitizer_cov_trace_func_enter" ||
-         Name == "___sanitizer_cov_trace_pc_guard";
+         Name == "___sanitizer_cov_trace_pc_guard" ||
+         // Large Aarch64 binaries use thunks
+         Name == "__AArch64ADRPThunk___sanitizer_cov" ||
+         Name == "__AArch64ADRPThunk___sanitizer_cov_with_check" ||
+         Name == "__AArch64ADRPThunk___sanitizer_cov_trace_func_enter" ||
+         Name == "__AArch64ADRPThunk___sanitizer_cov_trace_pc_guard";
 }
 
 // Locate __sanitizer_cov* function addresses inside the stubs table on MachO.