[CodeGen] Unify MBB reference format in both MIR and debug output

As part of the unification of the debug format and the MIR format, print
MBB references as '%bb.5'.

The MIR printer prints the IR name of a MBB only for block definitions.

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)->getNumber\(\)/" << printMBBReference(*\1)/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)\.getNumber\(\)/" << printMBBReference(\1)/g'
* find . \( -name "*.txt" -o -name "*.s" -o -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#([0-9]+)/%bb.\1/g'
* grep -nr 'BB#' and fix

Differential Revision: https://reviews.llvm.org/D40422

llvm-svn: 319665
diff --git a/llvm/test/CodeGen/AArch64/fast-isel-assume.ll b/llvm/test/CodeGen/AArch64/fast-isel-assume.ll
index d39a907..50f510a 100644
--- a/llvm/test/CodeGen/AArch64/fast-isel-assume.ll
+++ b/llvm/test/CodeGen/AArch64/fast-isel-assume.ll
@@ -3,7 +3,7 @@
 ; Check that we ignore the assume intrinsic.
 
 ; CHECK-LABEL: test:
-; CHECK: // BB#0:
+; CHECK: // %bb.0:
 ; CHECK-NEXT: ret
 define void @test(i32 %a) {
   %tmp0 = icmp slt i32 %a, 0