Revert "[Hashing] get_execution_seed: use a non-vague linkage symbol"

This reverts commit c00ada0.

Author: bnbarham

llvm/include/llvm/ADT/Hashing.h

@@ -308,13 +308,13 @@ struct hash_state {
 };
 
 /// In LLVM_ENABLE_ABI_BREAKING_CHECKS builds, the seed is non-deterministic
-/// per process (address of a function in LLVMSupport) to prevent having users
-/// depend on the particular hash values. On platforms without ASLR, this is
-/// still likely non-deterministic per build.
+/// (address of a variable) to prevent having users depend on the particular
+/// hash values. On platforms without ASLR, this is still likely
+/// non-deterministic per build.
 inline uint64_t get_execution_seed() {
 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
-  return static_cast<uint64_t>(
-      reinterpret_cast<uintptr_t>(&install_fatal_error_handler));
+  static const char seed = 0;
+  return static_cast<uint64_t>(reinterpret_cast<uintptr_t>(&seed));
 #else
   return 0xff51afd7ed558ccdULL;
 #endif