perf expr: Add < and > operators

perf expr: Add < and > operators

These are broadly useful but required to handle TMA metrics. For example
encoding Ports_Utilization from:

  https://download.01.org/perfmon/TMA_Metrics.csv

requires '<'.

  {
    "BriefDescription": "This metric estimates fraction of cycles the CPU performance was potentially limited due to Core computation issues (non divider-related).  Two distinct categories can be attributed into this metric: (1) heavy data-dependency among contiguous instructions would manifest in this metric - such cases are often referred to as low Instruction Level Parallelism (ILP). (2) Contention on some hardware execution unit other than Divider. For example; when there are too many multiply operations.",
    "MetricExpr": "( ( cpu@EXE_ACTIVITY.EXE_BOUND_0_PORTS@ + cpu@EXE_ACTIVITY.1_PORTS_UTIL@ + ( cpu@EXE_ACTIVITY.2_PORTS_UTIL@ * ( ( ( cpu@UOPS_RETIRED.RETIRE_SLOTS@ ) / ( cpu@CPU_CLK_UNHALTED.THREAD@ ) ) / ( ( 4.000000 ) + 1.000000 ) ) ) ) / ( cpu@CPU_CLK_UNHALTED.THREAD@ ) if ( cpu@ARITH.DIVIDER_ACTIVE\\,cmask\\=1@ < cpu@EXE_ACTIVITY.EXE_BOUND_0_PORTS@ ) else ( ( cpu@EXE_ACTIVITY.EXE_BOUND_0_PORTS@ + cpu@EXE_ACTIVITY.1_PORTS_UTIL@ + ( cpu@EXE_ACTIVITY.2_PORTS_UTIL@ * ( ( ( cpu@UOPS_RETIRED.RETIRE_SLOTS@ ) / ( cpu@CPU_CLK_UNHALTED.THREAD@ ) ) / ( ( 4.000000 ) + 1.000000 ) ) ) ) - cpu@EXE_ACTIVITY.EXE_BOUND_0_PORTS@ ) / ( cpu@CPU_CLK_UNHALTED.THREAD@ ) )",
    "MetricGroup": "Topdown_Group_Ports_Utilization",
    "MetricName": "Topdown_Metric_Ports_Utilization"
  },

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200610235823.52557-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>