dumpstate: Better format for dumping block stat

After CL the format looks like:

------ BLOCK STAT (/sys/block/mmcblk0) ------
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/stat                 :    11299    16093  1262592    31863     3895     2968    63232     6463        0    10260    38243
/mmcblk0/stat                 : perf(ios) rd: 75622KB/s(1322/s) wr: 18671KB/s(2246/s) q: 4
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p1/stat       :       37       29       66        6        0        0        0        0        0        6        6
/mmcblk0/mmcblk0p1/stat       : perf(ios) rd: 5632KB/s(6167/s) q: 1
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p24/stat      :       12       32      346        0        1        0        8        0        0        0        0
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p26/stat      :        0        0        0        0        3      381     3072      296        0      100      296
/mmcblk0/mmcblk0p26/stat      : perf(ios) rd: 0KB/s(0/s) wr: 15729KB/s(30/s) q: 3
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p30/stat      :       11       33      352       23        0        0        0        0        0       23       23
/mmcblk0/mmcblk0p30/stat      : perf(ios) rd: 7836KB/s(478/s) q: 1
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p38/stat      :        1        3       32        0        0        0        0        0        0        0        0
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p39/stat      :      816     1072    47000     3460        0        0        0        0        0      273     3460
/mmcblk0/mmcblk0p39/stat      : perf(ios) rd: 88147KB/s(2989/s) q: 13
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p40/stat      :       17       13      228        0        4        0       32        3        0        3        3
/mmcblk0/mmcblk0p40/stat      : perf(ios) rd: 0KB/s(0/s) wr: 5461KB/s(1333/s) q: 1
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p41/stat      :     4831    14319   453376    17336        0        0        0        0        0     3273    17330
/mmcblk0/mmcblk0p41/stat      : perf(ios) rd: 70898KB/s(1476/s) q: 5
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p42/stat      :        8      124     1056        3        0        0        0        0        0        3        3
/mmcblk0/mmcblk0p42/stat      : perf(ios) rd: 180224KB/s(2667/s) q: 1
Block-Dev                     :    R-IOs   R-merg   R-sect   R-wait    W-IOs   W-merg   W-sect   W-wait   in-fli    activ   T-wait
/mmcblk0/mmcblk0p45/stat      :     5560      468   760088    11033     3046     2587    60120     5490        0     6840    16453

Bug: 62319771
Test: adb bugreport and check the result
Change-Id: I9464c4758f03479d433bdb7a907dd4953f226e1e