[Courgette] Fix disassembler_elf_32_arm on_32bit tracking code

Previously, we used bitwise operations on booleans to keep track of
whether we are 32-bit aligned. This code ran afoul of Clang's new
-Wbool-operation and didn't implement the intended behavior. This
change fixes the bug uncovered by the warning and implements the
intended logic using boolean operations.

Bug: 1011810
Change-Id: I4a7275a4e8da274115fa8ae85c90448c036200ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1846481Reviewed-by: Samuel Huang <huangs@chromium.org>
Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Commit-Queue: Bob Haarman <inglorion@chromium.org>
Cr-Commit-Position: refs/heads/master@{#703866}

courgette/disassembler_elf_32_arm.cc

@@ -524,7 +524,7 @@ CheckBool DisassemblerElf32ARM::ParseRel32RelocsFromSection(
       // 0        | 0          1
       // 0        | 1          0
       // 1        | 1          1
-      on_32bit = (~(on_32bit ^ (op_size == 4))) != 0;
+      on_32bit = (on_32bit == (op_size == 4));
     } else {
       // Move 2 bytes at a time, but track 32-bit boundaries
       p += 2;