[Clang] Fix bugs the way we handle duplicate vs conflicting values with loop...

[Clang] Fix bugs the way we handle duplicate vs conflicting values with loop attribute 'code_align' (#87372)

https://github.com/llvm/llvm-project/pull/70762 added support for new
loop attribute [[clang::code_align()]].

This patch fixes bugs for the test cases below that misses diagnostics due to discontinue to while loop during checking duplicate vs conflicting code_align attribute values in routine CheckForDuplicateLoopAttrs().

[[clang::code_align(4)]]
[[clang::code_align(4)]]
[[clang::code_align(8)]]
for(int I=0; I<128; ++I) { bar(I); }

[[clang::code_align(4)]]
[[clang::code_align(4)]]
[[clang::code_align(8)]]
[[clang::code_align(32)]]
for(int I=0; I<128; ++I) { bar(I); }