Eliminate the first have of the optimization which eliminates BRCOND
when the condition is constant. This optimization shouldn't be
necessary, because codegen shouldn't be able to find dead control
paths that the IR-level optimizer can't find. And it's undesirable,
because it encourages bugpoint to leave "br i1 false" branches
in its output. And it wasn't updating the CFG.

I updated all the tests I could, but some tests are too reduced
and I wasn't able to meaningfully preserve them.

llvm-svn: 106748
diff --git a/llvm/test/CodeGen/Thumb2/ldr-str-imm12.ll b/llvm/test/CodeGen/Thumb2/ldr-str-imm12.ll
index b444b29..29b8e75 100644
--- a/llvm/test/CodeGen/Thumb2/ldr-str-imm12.ll
+++ b/llvm/test/CodeGen/Thumb2/ldr-str-imm12.ll
@@ -25,10 +25,7 @@
 ; CHECK:       ldr.w	r9, [r7, #28]
   %xgaps.i = alloca [32 x %union.rec*], align 4   ; <[32 x %union.rec*]*> [#uses=0]
   %ycomp.i = alloca [32 x %union.rec*], align 4   ; <[32 x %union.rec*]*> [#uses=0]
-  br i1 false, label %bb, label %bb20
-
-bb:                                               ; preds = %entry
-  unreachable
+  br label %bb20
 
 bb20:                                             ; preds = %entry
   switch i32 undef, label %bb1287 [