[clang] Install scan-build-py into plain "lib" directory (#106612)

Install scan-build-py modules into the plain `lib` directory,
without LLVM_LIBDIR_SUFFIX appended, to match the path expected
by `intercept-build` executable.  This fixes the program being unable
to find its modules.  Using unsuffixed path makes sense here, since
Python modules are not subject to multilib.

This change effectively reverts 1334e12.
The commit in question changed the path without a clear justification
("does not respect the given prefix") and the Python code was never
modified to actually work with the change.

Fixes #106608

(cherry picked from commit 0c4cf79)

Author: mgorny

clang/tools/scan-build-py/CMakeLists.txt

@@ -88,7 +88,7 @@ foreach(lib ${LibScanbuild})
                      DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/lib/libscanbuild/${lib})
   list(APPEND Depends ${CMAKE_BINARY_DIR}/lib/libscanbuild/${lib})
   install(FILES lib/libscanbuild/${lib}
-          DESTINATION lib${CLANG_LIBDIR_SUFFIX}/libscanbuild
+          DESTINATION lib/libscanbuild
           COMPONENT scan-build-py)
 endforeach()
 
@@ -106,7 +106,7 @@ foreach(resource ${LibScanbuildResources})
                      DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/lib/libscanbuild/resources/${resource})
   list(APPEND Depends ${CMAKE_BINARY_DIR}/lib/libscanbuild/resources/${resource})
   install(FILES lib/libscanbuild/resources/${resource}
-          DESTINATION lib${CLANG_LIBDIR_SUFFIX}/libscanbuild/resources
+          DESTINATION lib/libscanbuild/resources
           COMPONENT scan-build-py)
 endforeach()
 
@@ -122,7 +122,7 @@ foreach(lib ${LibEar})
                      DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/lib/libear/${lib})
   list(APPEND Depends ${CMAKE_BINARY_DIR}/lib/libear/${lib})
   install(FILES lib/libear/${lib}
-          DESTINATION lib${CLANG_LIBDIR_SUFFIX}/libear
+          DESTINATION lib/libear
           COMPONENT scan-build-py)
 endforeach()