Fixed undefined behavior trsm ukr bug in bdd46f9.

Details:
- Fixed a bug that mainfested anytime a configuration was used in which
  optimized microkernels were registered and the trsm operation (or
  kernel) was invoked. The bug resulted from the optimized microkernels'
  register blocksizes conflicting with the hard-coded values--expressed
  in the form of constant loop bounds--used in the new reference trsm
  ukernels that were introduced in bdd46f9. The fix was easy: reverting
  back to the implementation that uses variable-bound loops, which
  amounted to changing an #if 0 to #if 1 (since I preserved the older
  implementation in the file alongside the new code based on constant-
  bound loops). It should be noted that this fix must be permanent,
  since the trsm kernel code with constant-bound loops can never work
  with gemm ukernels that use different register blocksizes.

Author: fgvanzee

ref_kernels/3/bli_trsm_ref.c

@@ -34,7 +34,7 @@
 
 #include "blis.h"
 
-#if 1
+#if 0
 
 // An implementation that attempts to facilitate emission of vectorized
 // instructions via constant loop bounds + #pragma omp simd directives.