Memory leak with TracePoint on bmethod

[Bug #20194]

When disabling the TracePoint on bmethod, the hooks list is not freed.

For example:

    obj = Object.new
    obj.define_singleton_method(:foo) {}
    bmethod = obj.method(:foo)
    tp = TracePoint.new(:return) {}

    10.times do
      100_000.times do
        tp.enable(target: bmethod) {}
      end

      puts `ps -o rss= -p #{$$}`
    end

Before:

    18208
    22832
    26528
    29728
    34000
    37776
    40864
    44400
    47680
    51504

After:

    16688
    17168
    17168
    17248
    17696
    17760
    17824
    17824
    17856
    17920

0 files changed, 0 insertions, 0 deletions