Fix: Jemalloc settings not getting applied as version check fails

Some Linux multi lib setups have a helper include file for Jemalloc that
in turn includes the actual header file. This makes our version regex fail.

As the Jemalloc version we are checking for is no longer in any of
the currently supported LTS linux distros, we can safely drop it.

Pull Request: https://projects.blender.org/blender/blender/pulls/139225

build_files/cmake/Modules/FindJeMalloc.cmake

@@ -47,15 +47,6 @@ find_library(JEMALLOC_LIBRARY
     lib64 lib
 )
 
-if(JEMALLOC_INCLUDE_DIR)
-  set(_version_regex "^#define[ \t]+JEMALLOC_VERSION[ \t]+\"([^\"]+)\".*")
-  file(STRINGS "${JEMALLOC_INCLUDE_DIR}/jemalloc.h"
-    JEMALLOC_VERSION REGEX "${_version_regex}")
-  string(REGEX REPLACE "${_version_regex}" "\\1"
-    JEMALLOC_VERSION "${JEMALLOC_VERSION}")
-  unset(_version_regex)
-endif()
-
 # handle the QUIETLY and REQUIRED arguments and set JEMALLOC_FOUND to TRUE if
 # all listed variables are TRUE
 include(FindPackageHandleStandardArgs)