[llvm-debuginfo-analyzer] Fix crash with WebAssembly dead code (llvm#141616)

llvm#136772
Incorrect handling of 'tombstone' value for WebAssembly.

llvm-debuginfo-analyzer already uses the tombstone approach
to identify dead code. Currently, the tombstone value is
evaluated as std::numeric_limits<uint64_t>::max(). Which is
wrong as it does not take into account the 'Address Byte Size'
from the Compile Unit header.

Fix incorrect 'REQUIRES'. The correct value should be:

REQUIRES: webassembly-registered-target

Author: CarlosAlbertoEnciso

llvm/test/tools/llvm-debuginfo-analyzer/WebAssembly/wasm-32bit-tombstone.s

@@ -1,4 +1,4 @@
-# REQUIRES: x86-registered-target
+# REQUIRES: webassembly-registered-target
 
 # Test that DWARF tombstones are correctly detected/respected in wasm
 # 32 bit object files.