CMake: Fix LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING to be 1 or 0.

It has been introduced in #107278 but it was passing
"DISABLED" of LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING to cmakedefine01.

cmakadefine01 treats non-false-like strings as 1.
"DISABLED" is replaced with 1.

Author: chapuni

llvm/cmake/modules/HandleLLVMOptions.cmake

@@ -204,10 +204,13 @@ elseif( uppercase_LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING STREQUAL "COVERAGE_AND_
   set( LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING 1 )
   set( LLVM_ENABLE_DEBUGLOC_ORIGIN_TRACKING 1 )
 elseif( uppercase_LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING STREQUAL "DISABLED" OR NOT DEFINED LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING )
-  # The DISABLED setting is default and requires no additional defines.
+  # The DISABLED setting is default.
+  set( LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING 0 )
 else()
   message(FATAL_ERROR "Unknown value for LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING: \"${LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING}\"!")
 endif()
+# LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING (non-cached) is expected to be
+# 1 or 0 here, assuming referenced in #cmakedefine01.
 
 if(LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS)
   add_compile_definitions(EXPERIMENTAL_KEY_INSTRUCTIONS)