fate: add ADPCM 4XM test

Signed-off-by: Paul B Mahol <onemda@gmail.com>

tests/fate/adpcm.mak

+FATE_ADPCM-$(call DEMDEC, FOURXM, ADPCM_4XM) += fate-adpcm-4xm
+fate-adpcm-4xm: CMD = framecrc -i $(SAMPLES)/4xm/dracula.4xm -vn -map 0:6
+
 FATE_ADPCM-$(call DEMDEC, AST, ADPCM_AFC) += fate-adpcm-afc
 fate-adpcm-afc: CMD = framecrc -i $(SAMPLES)/ast/demo11_02_partial.ast
 

tests/ref/fate/adpcm-4xm

+#tb 0: 1/22050
+0,          0,          0,     1472,     5888, 0x9086e310
+0,       1476,       1476,     1472,     5888, 0xac8491f5
+0,       2952,       2952,     1472,     5888, 0xc9a08b6b
+0,       4428,       4428,     1472,     5888, 0x4cff893b
+0,       5904,       5904,     1464,     5856, 0xfb914624
+0,       7372,       7372,     1472,     5888, 0x1dd9781f
+0,       8848,       8848,     1472,     5888, 0x75937688
+0,      10324,      10324,     1472,     5888, 0x6c93a266
+0,      11800,      11800,     1464,     5856, 0xb14e6783
+0,      13268,      13268,     1472,     5888, 0x4d268759
+0,      14744,      14744,     1472,     5888, 0xce44b8c6
+0,      16220,      16220,     1472,     5888, 0xf99f7347
+0,      17696,      17696,     1464,     5856, 0x35591adc
+0,      19164,      19164,     1472,     5888, 0x67692338
+0,      20640,      20640,     1472,     5888, 0x6465addd
+0,      22116,      22116,     1472,     5888, 0x22c66aaf
+0,      23592,      23592,     1464,     5856, 0x016b78d9
+0,      25060,      25060,     1472,     5888, 0xa9a03855
+0,      26536,      26536,     1472,     5888, 0x1aa0603f
+0,      28012,      28012,     1472,     5888, 0x190a25a1
+0,      29488,      29488,     1464,     5856, 0xc6ad8bc0
+0,      30956,      30956,     1472,     5888, 0x42bb9d6b
+0,      32432,      32432,     1472,     5888, 0x797694d7
+0,      33908,      33908,     1472,     5888, 0xd2d1fa69
+0,      35384,      35384,     1464,     5856, 0x61624e9b
+0,      36852,      36852,     1472,     5888, 0x14bf8ec0