Add crash case crash-19-unable-to-encode-mcoperand.c

suite/regress/c-crashers/crash-19-unable-to-encode-mcoperand.c

+#include <keystone/keystone.h>
+int main(int argc, char **argv) {
+  int ks_arch = KS_ARCH_ARM, ks_mode = KS_MODE_LITTLE_ENDIAN;
+  unsigned char assembly[] = {
+    'C', 'p', 'S', ' ', 'L', ',', 'f', 0x00,
+  };
+  ks_engine *ks;
+  ks_err err = ks_open(ks_arch, ks_mode, &ks);
+  if (!err) {
+    size_t count, size;
+    unsigned char *insn;
+    ks_asm(ks, (char *)assembly, 0, &insn, &size, &count);
+    ks_free(insn);
+  }
+  ks_close(ks);
+}