meminfo: Add IsSmapsRollupSupported Api

Consolidate the checking of /proc/<pid>/smaps_rollup support
in libmeminfo and do it in a thread safe way.

Use the API in ProcMemInfo as well to eliminate the extra
parameters passed to SmapsOrRollup* methods.

Bug: 111694435
Test: libmeminfo_test 1 --gtest_filter=TestProcMemInfo.IsSmapsSupportedTest
Test: Tested with and without the smaps_rollup support in kernel.

Change-Id: I992057f06b54569025fa0cdade9618da2675d1de
Merged-In: I992057f06b54569025fa0cdade9618da2675d1de
Signed-off-by: Sandeep Patil <sspatil@google.com>